HELSINKI — Nuclear-armed submarines slip in and out of the frigid waters along the coast of Russia's Kola Peninsula at the northern edge of Europe. Missiles capable of destroying cities are stored by the dozens in bunkers burrowed into the inland hills.

Since the Cold War, this Arctic arsenal has been protected by a combat unit considered one of Russia's most formidable - the 200th Separate Motor Rifle Brigade - until it sent its best fighters and weapons to Ukraine this year and was effectively destroyed.

The 200th was among the first units to plunge into Ukraine on Feb. 24, as part of a fearsome assault on the city of Kharkiv. By May, the unit was staggering back across the Russian border desperate to regroup, according to internal brigade documents reviewed by The Washington Post and to previously undisclosed details provided by Ukrainian and Western military and intelligence officials.

A document detailing a mid-war inventory of its ranks shows that by late May, fewer than 900 soldiers were left in two battalion tactical groups that, according to Western officials, had departed the brigade's garrison in Russia with more than 1,400. The brigade's commander was badly wounded. And some of those still being counted as part of the unit were listed as hospitalized, missing or "refuseniks" unwilling to fight, according to the document, part of a trove of internal Russian military files obtained by Ukraine's security services and provided to The Post.

The brigade's collapse in part reflects the difficulty of its assignment in the war and the valiant performance of Ukraine's military. But a closer examination of the 200th shows that its fate was also shaped by many of the same forces that derailed Russian President Vladimir Putin's invasion plans - endemic corruption, strategic miscalculations and a Kremlin failure to grasp the true capabilities of its own military or those of its adversary.

After months of ceding territory and losing thousands of troops, Putin is now trying to salvage his grandiose aims with an entire force that resembles the 200th: badly depleted, significantly demoralized, and backfilled with inexperienced conscripts.

This reconstruction of the brigade's decimation is based on the document trove, interviews with members of the unit and their families, as well as accounts from officers in Ukraine's military units that faced the 200th in battle. Most spoke on the condition of anonymity to discuss sensitive intelligence or, in the case of Russian soldiers, to maintain their own security. The Russian Defense Ministry did not respond to requests for comment.

The record reveals a brigade in crisis, according to officials and experts who examined the documents at The Post's request.

"They are barely at 60 percent strength, being forced to rely on reinforcements that aren't near enough," Pekka Toveri, former director of Finland's defense intelligence service, said in an interview. "You have guys who are refusing to fight, guys who are missing. It all tells us that for Russia the war has gone terribly wrong."

The war continued to get worse for the 200th.

The unit's commander sustained such severe head injuries in a strike that he was left vomiting, disoriented and unable to remember battlefield events, and would soon have to be hospitalized, the internal brigade documents show. Many of the unit's most potent weapons, including mobile rocket launchers and tanks, were either destroyed or captured.

In the months since the May inventory, the brigade has sustained further losses in engagements including a July firefight in the northeastern village of Hrakove, and it was among the Russian forces routed in Ukraine's September offensive to recapture large parts of the Kharkiv region.

All the while, the brigade was being degraded from within. The skilled troops and professional officers sent into battle at the start of the war with state-of-the-art T-80BVM tanks have given way to an assemblage of poorly trained conscripts pressed into service with paltry or outdated gear.

Some of the brigade's own soldiers described its condition as dire.

"The unit is in a state of decay," said a soldier now serving in the 200th after being drafted under mobilization orders that Putin issued in September. He and others were initially issued "painted helmets from 1941 and vests without plates," he said in an interview with The Post this month. "They are not even training us. . . . They just tell you, 'You are a shooter now. Here you go, here is a machine gun.'"

In a war that has been disastrous for much of Russia's military, the dismemberment of the 200th stands out. It entered the conflict with better training, newer equipment and more experience - including prior combat missions in Ukraine - than most other units. Now, given the magnitude of its losses, one European military official said, it "cannot be considered a fighting force."

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In peacetime, the 200th is garrisoned at spartan bases that lie inside the Arctic Circle, less than 10 miles from Russia's border with Norway. The location in the municipality of Pechenga, northwest of Murmansk, underscores its mission: to serve as a wedge between the NATO powers to the west and the Barents Sea bases of Russia's Northern Fleet.

The ports, which served as a point of departure for the fictional submarine in "The Hunt for Red October," have existential significance in Russian strategic doctrine. The Northern Fleet forms the core of Russia's "second strike" nuclear capability, meaning that its subs are expected to maneuver into the Atlantic and unleash a final, cataclysmic barrage if the United States manages to knock out Russia's land-based missile silos.

The 200th is part of an interlocking system of defenses for the fleet and its bases, one that also relies on their remote location, layers of perimeter security and additional units on the Kola Peninsula.

Despite the stakes of this Arctic assignment, the 200th has repeatedly been tapped by the Kremlin for priority missions. Officers were sent to Syria to help President Bashar al-Assad maintain his grip on power and, according to Ukrainian officials and a report by the investigative outlet Bellingcat, the unit was clandestinely involved in Russia's 2014 attempt to seize territory in Ukraine's eastern Donbas region.

In January of this year, two heavily armed battalion tactical groups from the 200th began boarding trains for the Ukraine border. Images online show flatbed rail cars carrying tanks across a snow-swept landscape and soldiers playing cards in packed passenger cabins.

The troops, like others in the invading force, were led to believe they were deploying to take part in drills, according to Ukrainian officials citing accounts of captured 200th soldiers. Only at 3 a.m. on Feb. 24 were they told, "There will be shooting," an official said.

A convoy of about 100 brigade vehicles began streaming across the border that morning. Photos taken by civilians show one of the unit's tanks being used to set up a roadblock on the northern outskirts of Kharkiv - an attempt to impose order that soon proved futile.

By day's end, multiple units of the 200th had been ambushed or attacked, dozens of soldiers killed or wounded, and equipment including tanks and "Grad" mobile rocket launchers destroyed or abandoned on roadsides, according to Ukrainian and Western accounts.

The devastation was due in part to the 200th's drawing one of the most difficult tasks of the invasion. "The front they were assigned proved to be well defended with very motivated Ukrainians," a senior European intelligence official said.

The Ukrainian war plan was organized above all around protecting Kyiv, the country's capital, but it also called for multiple armored units, including the 92nd Mechanized Brigade, to focus their firepower on defending Ukraine's second-largest city - Kharkiv.

The punishment inflicted on the 200th in those early battles and dozens more that followed remain a point of martial pride for senior Ukrainian officers. "What's there to know about them?" Col. Gen. Oleksandr Syrsky, who later commanded the Kharkiv offensive, said recently in an interview when asked about the 200th. "They run away very well."

The brigade was also hobbled by problems that plagued other Russian units. It was low on food and fuel after consuming or selling critical stores in the weeks leading up to the invasion, officials said. Putin's decision to keep even senior advisers in the dark left commanders scant time to prepare troops, let alone coordinate attack plans with other units.

Stunned by Ukraine's resistance, the 200th spent the ensuing weeks fending off further attacks while digging into defensive positions north of Kharkiv, officials said. It was during this stretch that the brigade commander, Col. Denis Kurilo, 44, was severely injured in a strike that Western officials said obliterated his vehicle. Ukrainian officials initially reported that the strike occurred in late March and that Kurilo had been killed. But internal brigade records refer to a "combat injury dated April 22" that ultimately required him to be hospitalized.

Only hints of the carnage were made public back at brigade headquarters. In mid-March, the governor of Russia's Murmansk region, which encompasses the 200th's garrison, announced online that three soldiers and one officer had been killed in Ukraine, calling them "real heroes."

But these were only a small fraction of the true casualties.

The internal brigade records include a detailed count of surviving personnel in May after they had retreated across the Russian border into the Belgorod region. The authenticity of the documents was confirmed by Western security officials.

One page includes a table that lists 892 servicemen still "present" and attached to the two battalion tactical groups that had deployed from Pechenga in the run-up to the war. Officials with European security services that closely monitor the 200th said those two units had started out with a combined 1,400 to 1,600 soldiers.

One official described the damage that such losses would have done to the unit's effectiveness and morale as "catastrophic."

Among those remaining, the table lists 21 as hospitalized, six as missing and nine as "refuseniks." It also shows that the brigade was awaiting 138 reinforcements, though it does not indicate their training or background.

Wording at the top of the document indicates that it was to be approved on May 28 by Kurilo, suggesting that he was still with the unit despite his recent injury. A medical file in the trove, however, indicates that he was suffering severe symptoms from a "craniocerebral injury," including nausea, vomiting, memory loss and "short-term disorientation." It says he left the unit on July 11 to be treated at Burdenko military hospital in Moscow and was released in late August. The medical file also says his duties were temporarily assigned to another officer.

Kurilo, whose passport and military résumé also appear in the trove, could not be reached for comment. On Wednesday, a woman identifying herself as his wife answered a number associated with Kurilo. She said he had not served with the 200th for about half a year, a period that would correspond with the start of his hospitalization. She said he has since been transferred to another military unit and is unreachable.

The avatar for Kurilo's WhatsApp account is a "Z" sign used by Russian forces in Ukraine, along with Russian words meaning "for victory."

For all the seeming exactitude of the brigade's roll call record, certain categories are conspicuously missing. It does not say how many soldiers had initially been part of the two battalion tactical groups, and makes no mention of those wounded or killed to that point in combat.

Toveri, the former Finland intelligence chief, said the record appears to represent an effort by commanders to take stock of their force without accounting for the causes of its attrition.

"They just did new bookkeeping," Toveri said, adding that doing so would be consistent with a Russian military culture seen as more calloused than its Western counterparts about casualties. "They had been at war for three months and don't mention any killed in action," Toveri said. "Let bygones be bygones."

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The losses created a two-front crisis for the 200th: It was scrambling to find reinforcements back in Murmansk, even as the broken battalions in Belgorod were being ordered to return to Ukraine.

In a sign of growing desperation, the brigade in June began forming what it called a "mixed volunteer battalion" including sailors pulled off Northern Fleet ships, logistics specialists from depots and others often coerced into action despite having little or no experience or training in ground combat, according to Western officials.

The battalion remnants in Belgorod tentatively crossed back into Ukraine in late spring and took positions hugging the Russia border.

Ukrainian military officials described the returning 200th force, though degraded, as more professional than the Russian-backed separatists they had previously faced outside Kharkiv.

The 200th soldiers were less prone to talking on open phone lines, brought far greater firepower and proved adept at targeting, said Taras Shevchenko, commander of an artillery and reconnaissance unit in Ukraine's 127th Separate Territorial Defense Brigade.

In early June, he said, his unit encountered the 200th in the village of Velyki Prokhody, north of Kharkiv. The Ukrainians were caught off guard by a flurry of strikes, including one that tore off the third floor of a building being used as a base of operations, Shevchenko said, leaving him with a concussion.

After a series of inconclusive exchanges, Shevchenko said, he convinced Ukrainian artillery units to hold their fire for several days, hoping to create the impression they were low on ammunition as quadcopter drones were used to get a clearer fix on Russian positions.

Amid the lull, surveillance images showed 200th troops letting down their guard.

"Nothing was attacking them, so they could safely sunbathe," Shevchenko said. "They took outdoor showers. They were running around without body armor, without helmets."

Ukrainian forces took advantage by unleashing a 40-minute barrage involving mortars, tanks and Soviet-era artillery pieces, then launched a follow-on attack the next day after nightfall.

"They didn't know where to run," Shevchenko said. After the village was liberated, he said, he spoke with residents who estimated that about 100 Russian troops had died as a result of the two-day engagement, though there are no official numbers. He said the strikes dismantled vehicles that could have evacuated the wounded. "The locals said that many died during the night," Shevchenko said. "They just bled to death, because those who were injured - they couldn't evacuate them."

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In that one sequence, the 200th had shown that it could be both lethally effective and fatally undisciplined. The erratic performance is characteristic of a unit that Western security officials describe as one of Russia's higher-performing brigades but nevertheless plagued by systemic rot and dysfunction.

Attached to the elite Northern Fleet, 200th troops get special gear and training for Arctic conditions and are often first in line for Russia's most advanced equipment. In 2017, the brigade was the first in Russia's armed services to receive new T-80BVM tanks rolling off assembly lines.

And yet Westerners who ventured to Pechenga before Russia restricted travel describe the base as a grim garrison where officers neglected troops' morale and soldiers could seem clueless about the brigade's identity and mission.

Thomas Nilsen, editor of the Barents Observer - a Norwegian news site that closely follows the 200th - described an encounter several years ago with soldiers at a bar near the base who were oblivious to their proximity to NATO, until he pulled up a map on his phone to show them.

In 2020, three servicemen died - including one by suicide and another by choking on vomit - and several were injured in incidents that raised concerns about brigade conditions and safety, according to an investigation by the Russian news outlet Sever.Realii. One soldier was blinded and another reportedly lost a hand while training with a miniature drone armed with high-power explosives.

That same year, a warrant officer in the 200th posted videos on social media accusing superiors of neglect and corruption. One showed scenes of squalor in apartments reserved for officers, with rusted appliances, mold creeping up walls, and piles of trash stuffed into unoccupied units.

"This is how ensigns and officers of the Russian army live!" the warrant officer, Mikhail Balenko, said on the video, describing the compound with an expletive. "The brigade commander does not even come here. He doesn't care how his subordinates live."

In another video, Balenko accused commanders of stealing supplies, bribing military inspectors and selling fuel meant for brigade vehicles. Balenko did not respond to attempts to reach him for comment.

The war appears to have exacerbated these problems of morale and cohesion.

Dozens of soldiers in Pechenga refused to deploy during the initial months of the invasion, according to officials from Western security services. It's unclear what happened to them.

Ukrainian commanders described battles in which 200th soldiers wouldn't fight or defied orders. In mid-July, a Ukrainian reconnaissance unit captured audio of a Russian tank commander in Hrakove screaming at subordinates.

"Should I show you how to kill Ukrainians? I'll get in the tank myself," the commander shouted, shortly before the tank was destroyed by a Javelin missile, according to Oleksandr, a reconnaissance scout in Ukraine's 92nd Mechanized Brigade, who spoke on the condition that his surname not be published to maintain his security.

By the end of that battle, dozens of Russian troops had been killed or wounded and 12 tanks had been destroyed, Oleksandr said, adding that additional intercepts indicated that numerous soldiers had at one point or another refused to use their weapons.

The brigade documents also hint at inner turmoil. One set of files lists criminal referrals made to Russian military prosecutors regarding four 200th soldiers - a senior lieutenant, two corporals and a private.

Two were accused of the "illegal sale of explosives," and two others of "unauthorized abandonment of military unit." The documents indicate that prosecutors declined to proceed with charges against the soldiers, though no reasons are cited. The soldiers' surnames appear in the records, but attempts to reach them were unsuccessful.

Accurate casualty counts for the 200th remain elusive. No figures have been released by the brigade, and only a handful of soldier deaths have been acknowledged in public statements from the Murmansk government.

Still, there have been other clues to the war's toll on military families in Murmansk. In late August, the regional legislature passed a law providing free meals to schoolchildren whose parents were serving in Ukraine or had been killed or wounded, and announced that 1,274 students qualified.

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The 200th's involvement in the siege of Kharkiv concluded in September when it was routed near Kupiansk in the Ukrainian offensive, said Col. Pavlo Fedosenko, commander of Ukraine's 92nd Mechanized Brigade, the unit that delivered the blow and has faced off against the 200th more than any other.

Afterward, only fragments of a single battalion were left, composed of a hodgepodge of soldiers that bore little resemblance to the skilled units that had set out for Ukraine seven months earlier, Fedosenko said.

Most of the unit's officers had been killed or injured, Fedosenko said, and about 70 percent of its equipment - including about 32 tanks and 100 vehicles - had been destroyed or captured.

"Nothing of that brigade is left," he said in a recent interview with The Post. "It's completely wiped out."

Western security officials provided similar assessments. Because so many of its contract soldiers and senior members of its officer cadre were lost, "it will take years to rebuild the 200th," said a senior European intelligence official.

On Sept. 17, Kurilo left command of the brigade to become deputy chief of another motor rifle division, according to a copy of an order by Russian Defense Minister Sergei Shoigu that was in the document trove.

Remnants of the 200th later surfaced in the Luhansk region, where intercepted communications provided to The Post by a Ukrainian military official showed Russian officers raging about insubordination. In one exchange, a regimental commander berates a subordinate over soldiers abandoning their positions.

"I am f-----g tired after one and a half months of these people," the commander said. He goes on to describe platoons melting away and his efforts to drag soldiers back into battle. In one case, "there were 30 people leaving their positions, and now it is f-----g over 60, 75, maybe the entire platoon," he said. After listing similar problems in other units, he said, "What the f--- are you doing? Are you going to assemble the battalion or not?"

At least 20 of the 200th's troops were wounded in recent skirmishes in Luhansk, the Ukrainian intelligence official said. A fact sheet provided by the official lists the wounded soldiers' names and birth dates; their ages range from the low 20s to the early 50s.

Contacted by The Post, one of those soldiers acknowledged that he was at home recuperating, but declined to discuss his deployment or injuries in detail. He described himself as "a civilian person. I have a family, kids. I never even had a thought about needing to go fight" before being swept up by Putin's mobilization.

"When I was in the hospital, there were guys from Moscow, just simple guys, some worked in car repairs or some other places," he said. "They were just pulled out of their civilian lives and sent to 'take villages.'" Many were reassured that "we are going to be in the rear, not on the front line," he said. "But it turned out to be the opposite."

The soldier, who could face prison if caught speaking about the war, was one of a tattered group of about 500 conscripts who were sent to Ukraine in October as part of yet another attempt to replenish the 200th there, according to Western security officials. The conscripts' departure from the Kola Peninsula capped a remarkable hollowing out of a unit that is supposed to defend Russia's border with Norway, a NATO country, and with Finland, now seeking to join the alliance.

In August and September, Russia moved a squadron of bombers capable of carrying nuclear weapons to an air base near Finland, according to satellite images and a report in the Israeli press. Western officials said they interpreted that as a sign Russia is likely to rely more than ever on nuclear deterrence in the Kola Peninsula given the reduced state of the 200th and other units.

"In the Murmansk region we now have our borders bare," the wounded soldier said. "They are all empty now. No one is left there."

Miller reported from Helsinki, Oslo and London; Ilyushina from Riga, Latvia; Belton from London; Khurshudyan from Kharkiv and Kyiv; and Sonne from Washington. The Washington Post's Serhiy Morgunov in Kyiv contributed to this report.