MOSCOW (Reuters) - The Kremlin said on Monday that Russian President Vladimir Putin was serious about trying to find peace at talks he has proposed in Turkey but his spokesman said he could say no more about the talks after Ukraine demanded the Kremlin chief attend.

Putin on Sunday proposed direct talks with Ukraine aimed at ending the war, and, after U.S. President Donald Trump publicly told Ukrainian President Volodymyr Zelenskiy to accept, Zelenskiy said he would but that Putin should attend in person.

"We are committed to a serious search for ways of a long-term peaceful settlement," Kremlin spokesman Dmitry Peskov told reporters, referencing the failed 2022 talks between Russia and Ukraine.

Peskov said many leaders had welcomed Putin's approach.

"This approach, aimed precisely at finding a real diplomatic solution to the Ukrainian crisis, eliminating the root causes of the conflict and establishing lasting peace, has met with understanding and support from the leaders of many countries."

He cited positive reactions from U.S. President Donald Trump, Turkish President Tayyip Erdogan as well as from countries in the BRICS group and from countries in the former Soviet Union.

Before reporters could ask any more questions about the proposed talks, Peskov said: "That's all. I've said everything I could about this story."

Putin and Zelenskiy have not met since December 2019 and make no secret of their contempt for each other.

Putin's proposal for direct talks with Ukraine came hours after major European powers demanded on Saturday in Kyiv that Putin agree to an unconditional 30-day ceasefire or face "massive" new sanctions.

Germany's government said on Monday that European countries will start preparing new sanctions on Russia unless the Kremlin by the end of Monday starts abiding by a 30-day ceasefire.

"The language of ultimatums is unacceptable for Russia, it is not suitable. You can't use such language with Russia," Peskov said when asked about the German and other European warnings.

(Reporting by Dmitry Antonov; Editing by Mark Trevelyan/Guy Faulconbridge)