US President Donald Trump has said the United States will "take a pass" on brokering further Ukraine war talks unless there is quick progress from Moscow and Kyiv.
Mr Trump was speaking after Secretary of State Marco Rubio commented - following talks with European allies - that Washington would "move on" if a truce did not seem "doable" within days.
"Yeah very shortly," Mr Trump told reporters in the Oval Office when asked to confirm what Mr Rubio had said.
"No specific number of days, but quickly. We want to get it done."
Mr Trump refused to cast blame on either Russian President Vladimir Putin, who ordered the February 2022 full-scale invasion of pro-Western Ukraine, or Ukrainian President Voloydmyr Zelensky.
But he insisted both sides had to make progress.
"Now if for some reason one of the two parties makes it very difficult, we're just going to say: 'You're foolish. You're fools. You're horrible people' - and we're going to just take a pass," Mr Trump said.
"But hopefully we won't have to do that."
Mr Trump told reporters, however, that he did not want to say he was walking away from the talks. He said he still believed there is a good chance to end the conflict.
"It's coming to a head right now," he said.
Earlier, Vice President JD Vance said he was optimistic about the conflict coming to an end, as he met Italian Prime Minister Giorgia Meloni for the second time in 24 hours.
His comments came hours after Mr Rubio said the US President Donald Trump would walk away from trying to broker a Russia-Ukraine peace deal within days unless there were clear signs that a deal could be done.
Vance 'optimistic' about peace talks
Mr Vance saw Ms Meloni in Washington yesterday and the two have since flown to the Italian capital ahead of the Easter holidays.
"I want to update the prime minister on some of the negotiations between Russia and Ukraine ... even in the past 24 hours, we think we have some interesting things to report on," Mr Vance told reporters sitting alongside Ms Meloni.
"Since there are the negotiations, I won't prejudge them, but we do feel optimistic that we can hopefully bring this war, this very brutal war, to a close," he added.
The trip is also Mr Vance's first back to Europe since delivering a combative speech at the Munich Security Conference in February, in which he lambasted the EU's members on culture war issues while calling for the bloc to "step up" in managing its own security.
Mr Rubio said Mr Trump was still interested in a deal, but had many other priorities around the world and was willing to move on unless there are signs of progress.
"We're not going to continue with this endeavour for weeks and months on end. So we need to determine very quickly now, and I'm talking about a matter of days whether or not this is doable in the next few weeks. If it is we're in. If it's not, then we have other priorities to focus on as well," he said.
Mr Trump boasted repeatedly before returning for a second presidential term that he would end the Ukraine war within 24 hours. He claimed recently that he was being sarcastic.
Ukraine has agreed to a full temporary ceasefire and accused Russia of stalling on a deal to get a better negotiating position.
Mr Trump stunned Western capitals when he opened direct talks with Mr Putin in February, soon after taking office.
He said he hoped the Russian leader was not dragging his feet.
"I hope not," he said when asked if Mr Putin was stalling. "I'll let you know soon." he said.
Mr Trump denied that he was being "played" by the Russian leader, who denied Russia was going to invade right up until the eve of the attack.
"Nobody's playing me, I'm trying to help,"Mr Trump said.
Watch : US Secretary of State Marco Rubio speaks to the media
The US comments come after talks yesterday involving US and European officials on the three-year-old conflict.
The meetings included Mr Rubio, French President Emmanuel Macron, US envoy Steve Witkoff, British Foreign Secretary David Lammy, German officials and Ukrainian ministers.
France said the talks had launched a "positive process", as Europe seeks to be included in efforts to end the conflict.
They took place as Mr Trump's push to end the war stumbles, with Russia's President Vladimir Putin rebuffing a complete truce.
"Today in Paris, we launched a positive process in which the Europeans are involved," the French presidency said.
A new meeting of envoys from the US, France, Britain, Germany and Ukraine will take place next week in London, it added.
Mr Rubio later called Russia's Foreign Minister Sergei Lavrov to discuss the Paris meeting.
"President Trump and the United States want this war to end, and have now presented to all parties the outlines of a durable and lasting peace," Mr Rubio told his Russian counterpart, according to the US State Department.
"The encouraging reception in Paris to the US framework shows that peace is possible if all parties commit to reaching an agreement," he added.
In a statement, Russia's foreign ministry said Mr Lavrov "reaffirmed Moscow's readiness to continue collaborative efforts with American counterparts to comprehensively address the root causes of the Ukrainian crisis".
Mr Lavrov and Mr Rubio agreed on the need to maintain "prompt communication channels", in light of the London meeting next week, the statement said.
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Putin's order not to hit Ukraine energy targets has 'expired', says Kremlin
Meanwhile, a 30-day moratorium on striking Ukrainian energy infrastructure ordered by Mr Putin last month has "expired", the Kremlin said.
Russia announced the truce on 18 March following a call between Mr Putin and Mr Trump, but both Russia and Ukraine accused each other of repeatedly breaking it.
"The month has indeed expired," spokesman Dmitry Peskov said.
"As of this time, there have been no other instructions from the Supreme Commander-in-Chief, President Putin."
The short-lived moratorium was one of the few commitments Mr Trump had wrangled from Russia in his attempt to broker a ceasefire in the three-year conflict.
Mr Putin rejected a joint US-Ukrainian proposal for an unconditional and full ceasefire put to him before.
Ukrainian President Volodymyr Zelensky said Russia was never serious about the moratorium and that it was continuing to strike Ukraine's energy targets "despite Putin's words".
'Europeans at the table'
Mr Zelensky, who has clashed with Mr Trump, has praised the recent talks, saying it was important to work towards "real security" in Europe.
Posting on Telegram, Mr Zelensky's chief of staff Andriy Yermak thanked Mr Macron "for your efforts in the process of achieving a just and lasting peace for Ukraine".
However, Mr Peskov dismissed the Paris meeting, saying earlier that Europeans seemed to have "a focus on continuing the war".
France and Britain have sought a coordinated European response to defending Ukraine, during the conflict and in any ceasefire, after Mr Trump shocked them by opening talks with Russia.
Mr Macron said the Paris talks were "a very important occasion for convergence," as everybody wanted "a robust and sustainable peace".
French Foreign Minister Jean-Noel Barrot told reporters the talks had made a breakthrough because the United States, Ukraine, and European ministers had "gathered around the same table" when Europe had previously feared it would be excluded from decision-making.
The US "has understood that a just and sustainable peace ... can only be achieved with the consent and contribution of Europeans," he added later on LCI television.
