The announcement was made by leaders of Britain, France, Germany, Poland and Ukraine after a meeting in Kyiv, and a phone call with President Trump.

Speaking at the Kremlin in the early hours of Sunday, Putin proposed direct talks with Ukraine in Istanbul on May 15 -- hours after Kyiv and the leaders of France, Germany, Britain and Poland had called for an unconditional 30-day ceasefire to start on Monday.

Leaders from four major European countries have threatened to ratchet up pressure on Russian President Vladimir Putin if he does not accept an unconditional 30-day ceasefire in Ukraine that they offered in a strong show of unity with Kyiv.