Trump promised to end the war within 24 hours of returning to the White House, but as he celebrates 100 days in office, Rubio hinted that the administration may soon turn its attention to other issues.

"We are now at a point where both sides need to come forward with concrete proposals on how to end this conflict. If there is no progress, we will withdraw as mediators in this process," State Department spokeswoman Tami Bruce said, adding that this was Rubio's message.

She added that Trump would ultimately decide whether to continue diplomatic efforts.

Russian President Vladimir Putin recently proposed a three-day ceasefire during celebrations marking the 80th anniversary of the end of World War II next week.

However, Putin rejected the US-backed Ukrainian request for a 30-day ceasefire.

The United States wants "not three days so you can celebrate something else, but a complete and permanent ceasefire and an end to the conflict," Bruce said. | BGNES