But the US plan to recognise Russia's claim to Crimea would be a breach of Ukraine's constitution and so not something President Volodomyr Zelenskyy can agree to even if he wanted to keep the talks alive.
On today's Sky News Daily, Niall Paterson talks to our international affairs editor Dominic Waghorn about what will happen to Ukraine and Russia - and to the UK's and Europe's relations with the US - if Trump walks away from peace talks.
Producer: Soila Apparicio
Editor: Wendy Parker