MOSCOW/WASHINGTON (Reuters) - U.S. President Donald Trump's envoy, Steve Witkoff, will visit Moscow this week for a new round of talks with Russian President Vladimir Putin about the war in Ukraine, the White House said on Tuesday.

Witkoff has previously held three long meetings with Putin on prospects for an end to the war in Ukraine.

White House press secretary Karoline Leavitt said President Donald Trump had met Witkoff earlier in the day and "they wanted everyone to know that the negotiations continue" and that Witkoff was headed to Russia later this week.

Trump "wants to see peace, he wants this war to end" and he has grown frustrated with both sides of the war, she said.

Kremlin foreign policy adviser Yury Ushakov said earlier on Tuesday Witkoff would visit Moscow this week, according to Interfax.

The meeting comes as talks prepare to get under way in London on Wednesday regarding the war in Ukraine.

U.S. President Donald Trump's Ukraine envoy General Keith Kellogg will attend those meetings, U.S. State Department spokesperson Tammy Bruce told reporters at a separate briefing, with Secretary of State Marco Rubio no longer able to attend.

Ukrainian President Volodymyr Zelenskiy on Tuesday said he would be happy to meet with Trump later this week when they both attend the funeral for Pope Francis.

Zelenskiy, speaking to reporters in Kyiv, said Ukraine would be ready to hold talks with Russia in any format once a ceasefire is in place and the fighting between Kyiv and Moscow's forces has stopped.

Putin, meanwhile, has offered to halt his invasion of Ukraine across the current front line as part of efforts to reach a peace deal with Trump, the Financial Times reported on Tuesday.

Multiple sources say the U.S. last week had proposed recognizing Russia's illegal annexation of Crimea.

(Reporting by Reuters, Writing by Felix Light; Editing by Mark Trevelyan and Sandra Maler)