BERLIN — Ukraine’s top ​negotiator Rustem Umerov arrived in Berlin on Tuesday for talks, amid Russia’s warning to foreign diplomats to leave Kyiv due to planned airstrikes.

Two people familiar with the meeting, granted anonymity to speak freely about the sensitive discussions, told POLITICO that Umerov would meet the national security advisers of the E3 group of Germany, France and the U.K.

A spokesperson for German Chancellor Friedrich Merz declined to comment, citing a “confidential meeting.” The Ukrainian embassy in Berlin also declined to comment. Umerov, who is head of Ukraine’s national security committee, was in Brussels on Monday for talks with a top European Commission official over defense industry cooperation, and flew early Tuesday to Berlin.

The diplomatic engagement comes at a crucial moment after Russia executed a massive attack on Kyiv over the weekend and threatened further “consistent and systemic strikes.” The Russian foreign ministry urged diplomats and foreign citizens to leave the city “as soon as possible,” while the EU’s ambassador to Ukraine rejected the demand, saying, “We stay in Kyiv. We stay with Ukraine.”

U.S. Secretary of State Marco Rubio indicated Friday that America would backtrack from Ukraine peace talks it was leading, saying they “were not fruitful, unfortunately” and adding, “If someone else would like to handle it, they should.”

European officials have in recent weeks discussed whether to reach out directly to Russian President Vladimir Putin for negotiations, with names such as former German Chancellor Angela Merkel being floated for the role — although she said she wouldn’t be the right person.

German Foreign Minister Johann Wadephul told German daily Welt earlier this month that the E3 group was “making a fresh attempt to re-enter negotiations — with Europe playing a greater role in the coming weeks and months.” Merz hosted peace talks for Ukraine in Berlin in December, involving the Americans but not the Russians, with little progress.

The new E3 talks with Umerov in Berlin come amid simmering tensions between Merz and Zelenskyy after the German chancellor issued a letter offering Ukraine a downsized “associate membership” before potentially becoming a full EU member at a later stage. The Ukrainian president rejected Merz’s proposal over the weekend, saying that “Ukraine’s place in the European Union must also be complete, full and equal.”

Merz had previously suggested that this associate membership could be granted to Ukraine as a concession, allowing Zelenskyy to gain public support for ceding Russian-occupied territories as part of a peace settlement.

One EU diplomat, who was also granted anonymity to speak freely, said the timing was “noteworthy.”

“Last week, many in Brussels were asking why Merz makes his push for Ukraine’s associate membership public just at this moment,” the diplomat said. “The fact that Umerov is in Berlin today suggests there is a clear connection in the timing.”