PARIS, April 18 (Xinhua) -- The U.S. administration will stop pursuing a Russia-Ukraine peace deal unless it knows it is "doable" within days, U.S. Secretary of State Marco Rubio said on Friday.

"We're not going to continue with this endeavor 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," said Rubio after a trilateral meeting on Ukraine hosted by France.

It is the first time that the United States, Ukraine and Europe sat at the same negotiation table since U.S. President Donald Trump assumed office in January. Trump has been trying to broker a fast Russia-Ukraine peace deal, but the efforts have yielded no breakthrough so far.

On March 18, Trump proposed that both sides refrain from striking energy infrastructure facilities for 30 days. Russia and Ukraine then agreed. On Friday, Russia said Ukrainian forces have still been launching strikes on energy infrastructure in 15 Russian areas.