A major meeting in London aimed at bringing about an end to Russia’s war in Ukraine has been downgraded after US Secretary of State Marco Rubio said he would skip the summit, escalating a clash between Washington and Kyiv over the future of Russian-occupied Crimea.

Talks between the U.S., Ukraine and European officials to discuss ending Russia's war in Ukraine faltered as Secretary of State Marco Rubio abruptly cancelled his trip to London.

London discussions between the US, United Kingdom, Ukraine, France and Germany ended Wednesday without agreement on the terms of a potential peace deal — but with promises to keep talking, as Ukraine President Volodymyr Zelenskyy again insisted ceding Crimea to Russia was a non-starter.