US Secretary of State Marco Rubio on Friday said Washington needed to decide soon if a Ukraine truce was feasible, as he left Paris following meetings with European officials.
"We need to figure out here now, within a matter of days, whether this is doable in the short term, because if it's not, then I think we're just going to move on," he told reporters at the Le Bourget airport.
"If it is, we're in. If it's not, then... we have other priorities to focus on as well."
"The United States has been helping Ukraine over the last three years, and we want it to end, but it's not our war," Rubio added.
European powers have been seeking a seat at the table since US President Donald Trump blindsided Kyiv and European allies by agreeing to launch peace talks after a phone call with Russia's President Vladimir Putin.
But Trump's push to end the war has stumbled, with Putin rebuffing a complete truce.
Rubio, however, said European officials had been "very helpful and constructive with their ideas" during talks on Thursday.
"We'd like them to remain engaged... I think the UK and France and Germany can help us move the ball on this and then get this closer to a resolution," he said.
The top US diplomat said he also hoped that European nations would consider lifting sanctions against Russia imposed after it invaded Ukraine in 2022.
"Part of the sanctions against Russia, many of them are European sanctions that we can't lift, if that were ever to be part of a deal," he said.
European countries last month had agreed to ramp up rather than lift sanctions on Russia.
