President Trump and President Vladimir V. Putin of Russia reached no agreement to end the war in Ukraine at a high-profile summit meeting on Friday, although they reported making unspecified progress during a strikingly convivial reunion on American soil.

While Mr. Trump had hoped to seal a deal for an immediate cease-fire, he acknowledged that the two leaders fell short, at least for now. “We haven’t quite got there, but we’ve made some headway,” he told reporters after hours of meetings on a U.S. military base in Alaska. “There’s no deal until there’s a deal.”

But if the substance remained unsettled, the atmospherics were extraordinary. The president rolled out a literal red carpet and even applauded as he welcomed Mr. Putin, who is under U.S. sanctions and faces an international arrest warrant for war crimes. The two laughed and spoke warmly with each other, and Mr. Trump even invited Mr. Putin to ride with him in the armored presidential limousine to their meeting.

At their subsequent joint appearance at side-by-side lecterns at Joint Base Elmendorf-Richardson, they heaped praise on one another. “We really made some great progress today,” Mr. Trump said. “I’ve always had a fantastic relationship with President Putin, with Vladimir.”

Mr. Putin referred to Mr. Trump as a “dear neighbor” with whom he can do business. “President Trump and I have established a very good, businesslike and trustworthy contact,” he said in Russian.