WASHINGTON

US Secretary of State Marco Rubio warned Tuesday that Washington’s patience with Russia is not "infinite," urging intensified peace efforts while signaling that President Donald Trump is ready to impose "further costs" if negotiations fail.

"The president is a very patient man. He's very committed to peace, but his patience is not infinite," Rubio told a UN Security Council meeting on Ukraine.

He said Trump has refrained from additional sanctions in hopes of a breakthrough but stressed there may come a point when Washington concludes that Moscow has no interest in a peaceful resolution.

At that stage, Rubio noted, the administration is ready to impose “additional economic costs” on Russia.

"We've entered a period of what appears to be potentially even escalation, with some of the historically highest numbers of strikes we've seen over the last few nights and before. And now, we are also watching incursions into neighboring airspace by both drones and airplanes," he said, referring to alleged Russian violations of Estonia, Romania and Poland's airspace.

Rubio nevertheless stressed that the US is still open to a peaceful resolution to the Russia-Ukraine war.

“This war needs to end. But if it does not, if there is no path to peace in the short term, then the United States and President Donald J Trump will take the steps necessary to impose costs for continued aggression,” he said.

The remarks came hours after Trump, in a major shift, said Ukraine is now positioned to win back all its occupied territory, citing Russia’s “big economic trouble” and calling Moscow a “paper tiger.”

He made the comments on his Truth Social platform following a closed-door meeting with Ukrainian President Volodymyr Zelenskyy on the sidelines of the UN General Assembly in New York.