Major European powers threw their weight behind an unconditional 30-day Ukraine ceasefire on Saturday, with the backing of U.S. President Donald Trump, and threatened President Vladimir Putin with "massive" new sanctions if he did not accept within days.

Ukraine and key European leaders agreed Saturday to an unconditional 30-day ceasefire beginning May 12 with the backing of President Donald Trump, threatening Russian President Vladimir Putin with new "massive" sanctions if he failed to comply.

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.