People who are disappointed with the lack of quick progress toward peace in Ukraine have “inflated expectations,” President Vladimir V. Putin of Russia said on Friday, in his first public comments since President Trump called on him to end the war by late next week.

Mr. Putin didn’t directly respond to Mr. Trump’s ultimatum, made on Monday. The U.S. president threatened to apply financial penalties on Russia and buyers of its oil, which include China, India and Turkey, if Moscow failed to end the war within about 12 days.

As Mr. Trump has dialed up his rhetoric, Moscow has intensified attacks on civilian infrastructure in Ukraine — strikes that, according to Mr. Trump, demonstrate that the Russian leader isn’t interested in peace.

On Thursday, at least 31 people were killed and 150 more were injured when Russian missiles and drones rammed into several buildings in the capital Kyiv, turning the side of one apartment building into rubble.

Speaking to reporters during a visit Friday to a remote monastery in northwest Russia, Mr. Putin suggested people expressing frustration with the slow nature of peace talks had underestimated the task.

“All disappointments come from inflated expectations,” Mr. Putin said. “In order to solve the issue in a peaceful way, we need deep conversations, not in public, but in the silence of a negotiating process.”