A potential later meeting between the presidents of Ukraine, Russia and the US will be “more important”, Trump adds.

"Trump wants to exhaust all options to have a peaceful end to war," the White House said Thursday. Whether those "options" are good or bad for Ukraine is key.

Donald Trump and Vladimir Putin hold talks in Alaska on Friday, with the U.S. president's hopes of sealing a ceasefire agreement on Ukraine uncertain but with a last gasp offer from Putin of a possible nuclear deal that could help both men save face.