European officials are seeking commitments from the new US administration of President Donald Trump to take part in security guarantees for Ukraine as diplomatic pressure to end the Russian invasion mounts.

Putin has said repeatedly that he is prepared to negotiate an end to the war, which first began in 2014, but that Ukraine would have to accept the reality of Russian territorial gains, which are currently about 20% of its land. He also refuses to accept Ukraine joining Nato, the military alliance of Western countries.