Russia on Thursday rejected the idea of NATO countries sending peacekeeping troops to Ukraine in the event of a ceasefire in the war with Russia, saying such a move would threaten to cause an "uncontrollable escalation".

Donald Trump pledged to end the conflict in Ukraine, but the war has proved harder to solve than he once thought. Now, he says he'll sanction Russia.

NATO Secretary-General Mark Rutte has warned that a Russian victory over Ukraine would undermine the dissuasive force of the world’s biggest military alliance and could cost trillions of dollars to restore the organization's credibility.

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.