Ukraine resisted U.S. and Russian pressure to commit to attending another round of peace talks on Monday, saying it first needed to see Russian proposals, while a leading U.S. senator warned Moscow it would be "hit hard" by new U.S. sanctions, Reuters reported.

U.S. President Donald Trump has urged Moscow and Kyiv to work together on a deal to end their three-year-old war, and Russia has proposed a second round of face-to-face talks with Ukrainian officials next week in Istanbul.

Kyiv has said it is committed to the search for peace, but that it was waiting for a memorandum from the Russian side setting out their proposals.

"For a meeting to be meaningful, its agenda must be clear, and the negotiations must be properly prepared," Ukrainian President Volodymyr Zelenskiy wrote on X on Friday after hosting Turkey's foreign minister for talks in Kyiv, according to Reuters.

"Unfortunately, Russia is doing everything it can to ensure that the next potential meeting brings no results," he said, citing the lack of a document from Russia.