KYIV — As Russian forces continue their grinding advance toward the supply hub of Pokrovsk in eastern Ukraine, a new offensive appears to be nearly underway in the southeastern Zaporizhzhia region, Ukrainian troops said this week, in what would represent a major escalation along the 600-mile-long front.

A buildup of Russian troops in Ukraine’s southeast comes as uncertainty looms over how a Trump presidency will affect the war and whether the two sides will be pushed to the negotiating table. President-elect Donald Trump has long claimed he will put a quick end to the war, and some in Ukraine fear that would involve Kyiv capitulating to Russia.

Trump spoke by phone with Russian President Vladimir Putin last week and urged him not to escalate the war, in a call the Kremlin denies took place. In the week since, however, Russian forces have redoubled their efforts on several fronts.

Buoyed by the arrival of North Korean troops, they have launched a major assault in recent days in Russia’s Kursk region, where Ukrainian forces control territory they seized in an August cross-border offensive. They are also pushing to encircle the eastern town of Kurakhove, which could pave the way for an imminent assault on the rail hub of Pokrovsk — long a Russian objective, and already under regular attack.

This week, they also launched a major attack on the northeastern city of Kupyansk, which Russia occupied in 2022 before it was retaken by Ukrainian troops. On Wednesday, Ukraine’s General Staff reported that Russian assault troops, dressed in uniforms intended to resemble Ukraine’s, attacked Ukrainian positions in the Kupyansk direction with tanks and other armored vehicles.

There was also a major missile strike on Kyiv this week, after months of assaults by cheaper — and often less effective — drones.

The renewed Russian push, even as Trump’s win has spurred talk of a return to negotiations, has Ukrainian soldiers expecting little let up in the onslaught.

Roman, 22, a battalion commander in Ukraine’s 31st Brigade stationed directly south of the city of Orikhiv in the Zaporizhzhia region, said Russia is launching an assault from so many directions because Putin knows negotiations could be coming and “he will have much more leverage having control over all this territory as a result.”

Roman, who spoke on the condition he be identified only by his first name in keeping with military rules, has spent three months on the southeastern front, where he said Russia recently rotated out a highly trained air assault brigade and replaced it with a regular mechanized brigade.

The change has temporarily relieved some pressure on Ukrainian troops because the new brigade is equipped with fewer professional drone pilots and artillery pieces. But they know any reprieve is temporary: The rotation, Roman said, is likely to mean the Russian air assault troops — who held their positions for more than a year without rest — are taking a short break in the rear to reorganize and recruit before they deploy to attack weak spots on the front line.

Still, he said, the fight will not be easy for the Russians, who will face territory much more prepared for an advance than in the eastern region of Donetsk.

“There are significantly more fortifications in this area,” Roman said. “The second line of defense is practically stretching along the entire front line, plus it’s being built constantly.”

Yaroslav Galas, 52, a major in Ukraine’s 128th Mountain Assault Brigade deployed to the Zaporizhzhia front, said that after a long period of trading off “micro-advances” — in which the two sides would fight back and forth for control of a specific position — awareness is spreading that Russia is now preparing a major attack.

“The main sign is the clear buildup of larger Russian forces in the area. Additional units are being deployed — not just to the second or third lines but also to the front line,” he said, referring to aerial surveillance that has collected information on the arrival of new troops. “Our infantry units observe all this and understand that the Russians are preparing for something significant.”

The Russian troops sent to the Zaporizhzhia front appear “inexperienced and untested,” Galas said. Despite constant drone surveillance, these new forces have tried to advance in wheeled vehicles in broad daylight, making it easier for Ukraine to target and destroy them.

Ukrainian troops are trying to use the time before any major assault to place more mines and build new fortifications, Galas said.

But the looming offensive has injected anxiety into the surrounding area. Russian drones recently began reaching villages near the front line where children were still living, Galas said, prompting many residents to leave amid fears over a Russian escalation.

Russian forces have occupied parts of Zaporizhzhia region since 2022, including the nuclear power plant that Ukraine warns poses a major threat under Russian control. For Putin, advancing toward the regional capital would put a major prize within reach — and help in his bid to actually control a territory he declared part of Russia.

Lt. Serhiy Skibchyk, the head of communications for Ukraine’s 65th Mechanized Brigade, which is stationed near the village of Robotyne in the Zaporizhzhia region, also said Russian forces have recently intensified their assaults.

Over the summer, Russians regularly dropped glide bombs and other explosives on fields to identify land mines and Ukrainian positions, and now the infantry assaults are ramping up.

Late last week, Skibchyk said, 15 Russian troops on motorcycles tried to breach his brigade’s positions, but failed, and Ukrainian troops hunted them down in various hideouts throughout the day. This tactic has become common in the region, where Russia will launch simultaneous drone and infantry assaults to put pressure on Ukrainian troops.

Each day Russia loses between 10 and 20 soldiers launching these attacks. “We are doing everything possible to ensure that any potential enemy offensive in this sector is either thwarted entirely or ends in failure and high casualties,” Skibchyk said.

Any new Russian casualties join those from the attempted Russian offensive last spring.

“Their remains,” Skibchyk said, “still litter the fields and tree lines around Robotyne.”

previous coverage

• Kyiv’s European allies eye once-taboo ‘land-for-peace’ negotiations
• Ukrainian soldiers focus on keeping Russian advances at bay and brace for storm to come from US
• US to rush aid to Ukraine before Trump takes over, Blinken says