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.

A planned meeting Wednesday between top U.S., British, French and Ukrainian diplomats to push forward a peace deal between Russia and Ukraine was scrapped at the last minute, with U.S. Vice President JD Vance saying negotiations are reaching a moment of truth.

Secretary of State Marco Rubio’s last-minute decision to cancel means there will be no foreign ministers meeting in London for Ukraine peace talks, but presidential envoy Steve Witkoff will still go to Moscow.