By Jeff Mason and Steve Holland

WASHINGTON (Reuters) -U.S. President Donald Trump said on Friday he would like Russian President Vladimir Putin and Ukraine President Volodymyr Zelenskiy to "get this war ended" in Ukraine as he pushes for a 30-day ceasefire.

Trump, who departs on Monday on a trip to Saudi Arabia, United Arab Emirates and Qatar, was asked what his message to Putin is in the wake of a warning from the U.S. embassy in Kyiv about a "potentially significant" air attack in the coming days.

"I have a message for both parties: Get this war ended," Trump says of Ukraine and Russia. "Get this stupid war finished. That's my message for both of them," Trump told reporters in the Oval Office.

The embassy said on its website that it had received information about an air attack that may occur at any time over the next several days.

"The Embassy, as always, recommends U.S. citizens be prepared to immediately shelter in the event an air alert is announced," it said.

The White House said Trump had a "very good and productive" call with Zelenskiy on Thursday and that Trump hopes both Ukraine and Russia will agree next week to a proposed 30-day ceasefire.

White House spokeswoman Karoline Leavitt, speaking to reporters at a briefing on Friday, also reiterated that a Trump meeting with Putin next week in the Middle East was not going to happen.

In Kyiv, Zelenskiy's chief of staff, Andriy Yermak, said he spoke by telephone on Friday with U.S. Secretary of State Marco Rubio and other officials about the proposed ceasefire as part of moves towards a peace agreement.

"The main focus was the question of the ceasefire and prospects for a peace settlement," Yermak wrote on Telegram, adding that U.S. envoys Steve Witkoff and Keith Kellogg had also taken part. Ukrainian Defence Minister Rustem Umerov was also present.

"Also discussed was the importance of implementing the points on which our presidents agreed," Yermak wrote.

(Reporting by Jeff Mason, Steve Holland and Doina Chiacu; Editing by Ron Popeski and Alistair Bell)