Talks between the U.S., Ukraine and European officials to end Russia's war in Ukraine faltered on Wednesday as U.S. Secretary of State Marco Rubio abruptly cancelled his trip to London and negotiations were downgraded.

Diplomats from the UK, France, Germany, Ukraine and the US will hold fresh talks in London on Wednesday aimed at securing a ceasefire in the three-year war between Ukraine and Russia. The talks come amid growing speculation that Russia might be willing to halt its invasion along current front lines in return for significant concessions.