US President Donald Trump has set a new deadline of 10 to 12 days for Russia to make progress towards ending the war in Ukraine or face consequences, shortening a previous 50-day timeline.

President Trump threatened both sanctions on Russia and buyers of its exports unless progress is made, underscoring frustration with Russian President Vladimir Putin over the three-and-a-half-year conflict, the official White House channel recorded him as saying.

Speaking in Scotland during meetings with European leaders, Trump said he was disappointed in Putin and expressed impatience with the lack of progress on ending the war.

"I'm going to make a new deadline of about ... 10 or 12 days from today," Trump told reporters during a meeting with British Prime Minister Keir Starmer. "There's no reason in waiting... We just don't see any progress being made."

Former Russian President Dmitry Medvedev, a close Putin ally, said in a post on X that Trump was playing "a game of ultimatums" that could lead to war involving the US.

Ukraine welcomed Trump's statement, with President Volodymyr Zelenskyy's chief of staff Andriy Yermak thanking Trump for "standing firm and delivering a clear message of peace through strength."

Trump indicated he was not interested in more talks with Putin and said sanctions and tariffs would be used as penalties for Moscow if it did not meet his demands.

"There's no reason to wait. If you know what the answer is going to be, why wait? And it would be sanctions and maybe tariffs, secondary tariffs," Trump said. "I don't want to do that to Russia. I love the Russian people."

Ukraine had proposed a summit between Putin and Zelenskyy before the end of August, but the Kremlin said that timeline was unlikely and that a meeting could only happen as a final step to clinch peace.

Russia's foreign ministry said on Saturday that if the West wanted real peace with Ukraine, it would stop supplying Kyiv with weapons.

Trump expressed exasperation with Putin for pursuing attacks on Ukraine despite US efforts to end the war. "We thought we had that settled numerous times, and then President Putin goes out and starts launching rockets into some city like Kyiv and kills a lot of people in a nursing home or whatever," Trump said.