President Vladimir Putin’s conditions for ending the war in Ukraine include a demand that Western leaders commit in writing to halt NATO’s eastward expansion and lift some sanctions on Russia, three Russian sources familiar with the negotiations said.

U.S. President Donald Trump has repeatedly said he wants to end Europe’s deadliest conflict since World War II and has shown growing frustration with Putin in recent days, warning on Tuesday that the Russian leader was “playing with fire” by refusing to engage in ceasefire talks with Kiev as his forces made advances on the battlefield.

Russia also wants Ukraine to be neutral, some Western sanctions to be lifted, the issue of frozen Russian sovereign assets in the West to be resolved and Russian speakers in Ukraine to be protected, the three sources said, reports Telegrafi. The first source said that, if Putin realizes that he is unable to reach a peace agreement on his terms, he will try to show Ukrainians and Europeans through military victories that “peace tomorrow will be even more painful.”

Putin and Russian officials have repeatedly said that any peace agreement must address the “root causes” of the conflict – Russian reluctance on the issue of NATO enlargement and Western support for Ukraine. Kiev has repeatedly said that Russia should not be given the right to veto its aspirations to join the NATO alliance. Ukraine says it needs the West to give it a strong security guarantee by force to deter any future Russian attack. NATO has also said in the past that it will not change its “open door” policy just because Moscow demands it.

Russia currently controls just under a fifth of the country. Although Russian advances have accelerated over the past year, the war is costing both Russia and Ukraine dearly in terms of casualties and military spending.

Reuters reported in January that Putin was increasingly concerned about the economic distortions in Russia’s wartime economy, amid a labor shortage and high interest rates imposed to curb inflation. The price of oil, the bedrock of Russia’s economy, has fallen steadily this year.

Trump, who boasts a friendly relationship with Putin and has expressed confidence that the Russian leader wants peace, has warned that Washington could impose further sanctions if Moscow delays efforts to find a solution. Trump suggested on social media on Sunday that Putin was “completely crazy,” ordering a massive airstrike on Ukraine last week.

The first source said that if Putin saw a tactical opportunity on the battlefield, he would push further into Ukraine — and that the Kremlin believed Russia could fight for years despite sanctions and economic pain imposed by the West.

A second source said Putin was now less inclined to compromise on territory and was sticking to his public stance that he wanted the entirety of the four regions in eastern Ukraine claimed by Russia.