BERLIN — When 13,000 demonstrators gathered at the Brandenburg Gate on Feb. 25 to call for an end to weapons supplies to Ukraine, the protest was led by Sahra Wagenknecht, a member of parliament for Germany's far-left Die Linke party and a firebrand with national ambitions. Wagenknecht decried the prospect that German tanks, soon to be delivered to Ukraine, could once again be used to shoot at "Russian women and men."

"We don't want Germany to be drawn deeper into this war," she said, as she called for the creation of a new peace movement and condemned the bloodshed in Ukraine, without mentioning Russia's invasion.

Among the crowd in Berlin was Jürgen Elsässer, editor of a far-right-wing magazine, and dozens of members of the far-right Alternative für Deutschland (AfD) party who cheered Wagenknecht's calls to cut off Ukraine. Elsässer's Compact magazine had recently declared on its cover that Wagenknecht was: "The best chancellor - a candidate for the left and the right."

The coming together of political opposites in Berlin under the banner of peace had been percolating for months, though the union remains ad hoc and unofficial. But marrying Germany's extremes is an explicit Kremlin goal and was first proposed by senior officials in Moscow in early September, according to a trove of sensitive Russian documents largely dated from July to November that were obtained by a European intelligence service and reviewed by The Washington Post.

The documents record meetings between Kremlin officials and Russian political strategists, and the Kremlin's orders for the strategists to focus on Germany to build antiwar sentiment in Europe and dampen support for Ukraine. The files also chronicle the strategists' efforts to implement these plans and their reports back to the Kremlin. The documents do not contain any material that records communications between the Russian strategists and any allies in Germany. But interviews show at least one person close to Wagenknecht and several AfD members were in contact with Russian officials at the time the plans were being drawn up.

The documents - details of which were broadly corroborated by officials in Western governments - show for the first time the Kremlin's direct attempts to interfere in German politics by seeking to forge a new coalition among Wagenknecht, the far left and the AfD, as well as to support protests by extremists on the left and right against the German government.

The aim of a new political formation, according to a document dated Sept. 9, would be to win "a majority in elections at any level" in Germany and reset the AfD to boost its standing beyond the 13 percent the party was polling at then. The reset, laid out among the documents in a proposed manifesto for the AfD that was written by Kremlin political strategists, includes forging the AfD into the party of "German unity" and declaring sanctions on Russia as counter to German interests.

"Inadequate politicians, unable to calculate the consequences of their decisions, have dragged Germany into conflict with Russia - a natural ally of our country and of our people," the manifesto stated. "Our interests demand the restoration of normal partnership relations with Russia. ... Today in Germany there are only two parties: the party of enemies of Germany and the party of its friends." It is unclear from the documents if the manifesto ever reached anyone in the AfD.

Efforts to build antiwar sentiment in Germany are part of a hidden front in Russia's war against Ukraine as the Kremlin tries to undermine Western unity and freeze the war on its terms. Exploiting peace protests to divide the West repeats tactics that were first honed in Soviet times, and have come back to the fore since Russia's invasion of Ukraine. Elsässer, 66, who has migrated from the Communist left to the far right over the course of his political life, first led demonstrations in the 1980s against the deployment of U.S. Pershing II missiles in West Germany. His Compact magazine is now described by German officials as a Kremlin propaganda outlet.

"We know [these tactics] from the Cold War, when the Soviets tried to influence and manipulate the antiwar movements," said a senior German security official who, like others, spoke on the condition of anonymity to discuss sensitive matters.

The files indicate that on July 13, first Kremlin deputy chief of staff Sergei Kiriyenko assembled a group of Russian political strategists and told them that Germany was to become "the focus" of Moscow's efforts to undermine support for Ukraine in Europe.

The Kremlin's proposed strategy would draw together two German factions with long-standing pro-Russian stances. Wagenknecht, 53, is a former Communist who grew up in East Germany and has clashed several times with the more traditional leadership of Die Linke, including over her populist stance against unauthorized immigration and her claims that the party was too focused on left-wing academic elites, not the working class.

Opinion polls show that her popularity is growing nationally and she is openly mulling forming a new party. German pundits predict she would draw support from the AfD's base, and overall could garner up to 24 percent of the national vote, according to a recent poll cited by the German magazine Der Spiegel, which just put Wagenknecht on its cover.

Wagenknecht said in a statement to The Post that there would not be "any cooperation or alliance" between her "and elements of the AfD in any form." She said that any suggestion that she may have received communications from Russian officials or their representatives proposing an alliance with the AfD was "absurd," adding that she had "not been in contact with anyone from the Russian state or any of its representatives."

The AfD - called the party of "Putin understanders" by some in Germany - has echoed the Kremlin's view that the war in Ukraine was triggered by the United States and that Russia was simply defending itself from NATO encirclement while protecting Russian speakers in eastern Ukraine. Moscow has long cultivated dozens of AfD members, especially through lavish, all-expenses-paid trips to Russia, documents and interviews show.

It is not clear from the documents how the political strategists working with the Kremlin attempted to communicate with members of the AfD or other potential German allies about Moscow's plans. But soon after the Kremlin gave the order for a union to be forged between Wagenknecht and the far right, AfD deputies began speaking in support of her in parliament and party members chanted her name at rallies. Björn Höcke, chairman of the AfD in Thüringen in eastern Germany, publicly invited her to join the party.

The AfD as well as its co-leader Tino Chrupalla declined to comment in response to questions about the alliance and whether the AfD had received any communications from the Kremlin or individuals close to it proposing such a union.

Some in the AfD described the Russian effort as predictable but not necessarily having any actual role in charting the party's direction, especially since the two German camps held diametrically opposed views on running the economy. "Of course, the Russians are going to make use of every opportunity, but for them it is only theory," said one AfD member of parliament, speaking on the condition of anonymity to discuss sensitive party matters. "It is some kind of theoretical battle plan. But it is not what we are practicing here."

Kremlin spokesperson Dmitry Peskov denied that the Kremlin was involved in any efforts to interfere in German politics. "This is 100 percent fake," Peskov told The Post. "We never interfered before and now we really don't have time for this."

At least two key figures - one in the AfD and another close to Wagenknecht - said they were in contact with Kremlin officials or Kremlin allies at the time Moscow's proposals for a coalition were being drawn up. In addition, three AfD lawmakers traveled to Russia on Sept. 20 but broke off the trip after less than a day following a public outcry - and censure from the AfD party leadership - over their plans to visit Donbas, the region in eastern Ukraine that is illegally occupied by Russia.

One of the individuals in contact with Russian officials was Ralph Niemeyer, Wagenknecht's ex-husband. He told The Post that he was still in near-daily communication with Wagenknecht and that during recent meetings with top-level Kremlin officials in Moscow it was clear to him that "there are certain people in Russia who have [an] interest" in a union between Wagenknecht and the far right.

"I know from private talks with these people that they are aware of the potential that this would have," said Niemeyer, whose house was raided in late March as part of a criminal investigation over his alleged involvement in a plot by the ultra-right Reichsbürger movement to overthrow the German government - allegations that Niemeyer denies.

Despite the Kremlin's interest, Niemeyer said, Wagenknecht would never accept any support from Moscow. "That would immediately destroy this project because ... you saw it with Marine Le Pen in France. She only borrowed some money from some Russian bank, and not even a donation, and that cost her the presidency. Sahra can't make that mistake."

Wagenknecht said she would not comment about her private contacts in response to a question about whether she was in frequent communication with Niemeyer.

The other individual was Petr Bystron, a charismatic AfD member of parliament. Bystron traveled secretly to Belarus for three days in November; he only acknowledged the trip after it was exposed by Lithuanian and German media. Bystron told The Post that he met with the Belarusian foreign minister and that the visit was a fact-finding mission to prepare an AfD peace initiative, not to discuss German politics. He said he did not meet with any Russian officials. An earlier trip he made to Kyiv to visit Viktor Medvedchuk, a close ally of Russian President Vladimir Putin who was under house arrest, not long before Russia's invasion had also raised concerns among European officials, according to a European security official.

In early July, Putin declared that "even in the countries that are still satellites of the United States, there is a growing understanding that their ruling elites' blind obedience to their overlord, as a rule, does not necessarily coincide with their national interests, and most often simply and even radically contradicts them."

Days later, Kiriyenko summoned the political strategists to the Kremlin, and they began to try to exploit the perceived contradiction identified by Putin, the documents show. The political strategists had been told at the meeting with Kiriyenko that their main target was Germany, where they were to discredit the European Union, the United States, Britain and NATO while convincing Germans they were being harmed by the sanctions imposed on Russia, one of the documents dated July 13 shows. The share of the German population in favor of improving relations with Russia, Kiriyenko demanded, was to be boosted by 10 percent within a three-month time frame, a later document shows.

The Russian political strategists rued the difficulty of their task. "This is going to be complicated," one of them noted. They immediately scrambled to work with Russian troll farms to pump out slogans for German social media platforms and protests - "Buy gas, not war" and "Ukraine wants war, Germany want peace." Preparing slogans for protests over soaring energy costs formed another part of the strategy, according to the documents, though that issue failed to get much traction because of a mild winter in Europe and the German government's ability to diversify energy supplies.

The campaign even extended to graffiti to be painted on walls across Germany and then photographed and placed in the German press, the documents show. These included a drawing of a fat "Uncle Sam" saying, "Bear it a few more years." Another depicted German Foreign Minister Annalena Baerbock sitting on the Nord Stream natural gas pipeline connecting Russia and Germany, waving a Ukrainian flag and saying, "I don't care what the Germans think." It is unclear whether any of this graffiti appeared.

The strategists reported their progress at least once a month to Kremlin officials, the documents show, using a dashboard presentation to demonstrate the reach of their social networks, Telegram accounts and other media, such as a YouTube talk show, "Understanding the Russians," set up in August.

By late August, the documents show, the strategists were compiling information about planned protests across Germany, from Neustrelitz, a small town north of Berlin, to Stuttgart in the west. The protests were to take place under the leadership of the far left or the far right, including demonstrations to be led by the Reichsbürger movement. The strategists hoped to use the rallies as an opportunity to promote their own agenda, a security official familiar with the documents said, adding that they may have initiated some of the protests.

Demonstrators taking part in protest walks held every Monday in Leipzig and Neustrelitz carried slogans drawn up by the Kremlin strategists, demanding in Leipzig: "Launch Nord Stream 2 immediately!", "Lift the anti-Russian sanctions!" and "Lower electricity prices!" In Neustrelitz, they declared: "We want to live and not just survive!" and "What are we going to warm ourselves with in winter?"

For many AfD members of parliament, the party's alignment with Russia over the war in Ukraine, and with the Kremlin's anti-LGBTQ and anti-globalist agenda, is natural - and, they insist, not dictated by Moscow. The party was founded in 2013 in opposition to the German government's handling of the euro-zone crisis, but it soon took ever-harder right-wing stances: anti-immigration and railing against what party members saw as Germany's Atlanticist and liberal ruling elites.

"Normally, defending Ukraine would coincide with our own interests in the idea of national sovereignty. We believe in a Europe of fatherlands," said Andreas Kalbitz, former chairman of the AfD in Brandenburg and a member of the party's executive board until 2020, when he was ousted over his membership in a neo-Nazi group. "But this is a proxy war. And for many conservative people, Putin is the only big player working against the whole idea of Western liberalism. ... You have to choose one side, especially in wartime. But you can't say AfD is some kind of fifth column."

Kalbitz, like many other AfD members of parliament, was a frequent guest in Moscow. The AfD lawmakers' expenses, documents from the trove show, were often paid out of the Kremlin kitty, often through the "Russian Peace Foundation," an organization chaired by the Russian parliament's foreign affairs committee chief, Leonid Slutsky. The foundation "will cover the expenses for your trip to Russia," said one such invitation from Slutsky to Kay Gottschalk, an AfD MP, dated Oct. 3, 2018, according to one of the documents. Gottschalk declined to comment.

Kalbitz insisted his Kremlin hosts had never offered the party money - and noted that Alexander Gauland, one of the AfD's founding fathers, said the party would never accept if offered. But he conceded that he could not speak for every AfD lawmaker and said the Russians had frequently wowed their guests with sumptuous hospitality. In his case, that included an evening in one of St. Petersburg's most ornate imperial palaces, the Yusupov Palace, rented out solely for the handful of AfD visitors and their Kremlin-connected hosts, complete with a private performance by soloists from the Bolshoi Theater. "The Russians believe they can do most things with money," Kalbitz said.

Leaked emails from Russian officials, including an attache in the Russian Embassy in Berlin, previously reported in Der Spiegel in cooperation with the Dossier Center in London, have offered some insight into how the Russians viewed their German guests. "We will have our own absolutely controlled MP in the Bundestag," one April 2017 email said of Markus Frohnmaier, an AfD member of parliament and a guest on several junkets. Frohnmaier has previously denied the assertion and didn't respond to a request for comment from The Post.

AfD members and Niemeyer have continued to travel to Russia since the war began. When Niemeyer traveled to Vladivostok, a Russian city in the Far East, in September, he posted images on social media of his meetings at an economic forum with Peskov, Foreign Minister Sergei Lavrov and Alexei Miller, chief executive of Gazprom, the Russian state gas giant.

Niemeyer said at the time he was there to negotiate a new gas supply contract through Nord Stream 2 with Moscow, on behalf of what he called "a German government in exile."

The aim of the exercise was clear: a publicity stunt to try to put pressure on the government of Chancellor Olaf Scholz to seek a new relationship with Moscow as German businesses smarted from soaring energy costs. Niemeyer told The Post he delivered a copy of the proposed contract to the chancellor's office, and then told Alice Weidel, the AfD co-leader, who raised the issue with Scholz in parliament.

"She said, 'What if we found out later that you were sitting on an offer from Gazprom and you didn't sign it?'" Niemeyer said.

Niemeyer said he returned to Moscow following the Baltic Sea explosions that damaged the Nord Stream pipelines in September and was told by a top Kremlin official, Yury Ushakov, that supplies could still be delivered through Nord Stream 2, where one branch was undamaged in the explosions. During these meetings, he said, he was given a special encrypted telephone for communicating securely with Peskov, who, he said, is also interested in the effort to unite Wagenknecht and the AfD. Peskov did not respond to a request for comment about whether he gave an encrypted phone to Niemeyer.

"Peskov doesn't openly speak about that because he can't be quoted as saying, 'We wish this happens in Germany.' That's domestic policy," he said. "But I know from private talks with these people they are aware of the potential this would have. ... That's why I am talking to people who are more right-wing and saying, 'Let's forget about all the differences we have.'"

The idea of union with the AfD, he said, has so far not sat well with his ex-wife. Even though at the Feb. 25 protest, Wagenknecht said she welcomed everyone who was "pure in heart" and for peace and negotiations with Russia, she has balked at openly seeking an alliance with the far right, fearing it would cost her support on the left. Niemeyer said that if she formed her own party, she could garner about 10 to 20 percent of the national vote, drawing some AfD support. But if she officially forged an alliance with the AfD, Niemeyer asserted, without citing any specific polling, "she would probably be given a majority."

"She is immensely popular in Germany, so she would win the chancellorship with that, yes," he said, adding that he was already preparing a platform for Wagenknecht in hope that calls from Germany's main opposition party, the Christian Democratic Union, for a parliamentary inquiry over Scholz's handling of a tax fraud scam before he became the country's leader could lead to early elections. The Russians "would immediately support her," Niemeyer said, after spending a further two weeks in Moscow in April.

Some in the AfD are wary of joining forces with Wagenknecht, fearing she will end up diluting the potential of the party as a national force. While such an alliance could win AfD votes in east Germany, it would cost the party in the west, Kalbitz said. "Without the western part of Germany, the AfD will have no future on the level of the whole republic. We don't intend to lose our standing. I don't want to have one piece of cake when I can have the whole bakery. ... We are not here to fulfill Russian dreams."

But for Bystron, the AfD spokesperson on foreign policy, an alliance with Wagenknecht is attractive. "It is visible that on one side there is the globalist coalition and on the other side the populists, in the positive sense of the word."

Bystron insisted any such alliance was happening naturally and had nothing to do with any Kremlin plans. AfD supporters had first joined with the far left for protests against restrictions during the pandemic, he said. "This coalition is already [here]," he said. "The people are on the streets. They are already there. They are standing side by side."

Harris reported from Washington. The Washington Post's Loveday Morris in Berlin contributed to this report.