President Donald Trump announced Monday that he is reducing his deadline for Russian president Vladimir Putin to reach a ceasefire in Ukraine to "10 or 12 days," citing a lack of progress and saying he is "not so interested in talking anymore."

"I'm going to make a new deadline of about 10, 10 or 12 days from today," Trump told reporters during a meeting with U.K. prime minister Keir Starmer, adding, "There's no reason in waiting. There's no reason in waiting. [It was] 50 days—I want to be generous. But we just don't see any progress being made."

"I'm not so interested in talking anymore," Trump said of Putin.

Trump earlier this month gave Russia 50 days to end the war, threatening 100 percent tariffs on Moscow's trading partners unless Russia and Ukraine agree to a ceasefire. "We're going to be doing very severe tariffs if we don't have a deal in 50 days," Trump said on July 14. "It's very simple, and they'll be at 100 percent."

Russia had already dismissed the 50-day deadline before Monday's announcement, calling it "unacceptable."

Trump looks to ramp up pressure on Putin to stop Russia's three-year-long war on Ukraine. On July 14, the president said NATO allies will pay for 17 U.S.-made Patriot missile defense systems and deliver them to the Ukrainians. He has reportedly also asked Ukrainian president Volodymyr Zelensky whether Ukraine could hit military targets deep within Russia if the United States supplied long-range weapons.

The president reiterated on Monday that he is "disappointed in President Putin," as the Russian leader "goes out and starts launching rockets into some city, like Kyiv, and kills a lot of people in a nursing home or whatever—you have bodies lying all over the street."