WASHINGTON

US President Donald Trump said Friday that he and his Russian counterpart, Vladimir Putin, made “great progress” at a historic summit in Alaska, but acknowledged that they did not reach an agreement to end the war in Ukraine.

Putin and Trump struck upbeat notes after they met behind closed doors for more than three hours, with the US president saying they "had a very productive meeting."

"There were many, many points that we agreed on, most of them, I would say, a couple of big ones that we haven't quite gotten there, but we've made some headway. So, there's no deal until there's a deal," Trump told reporters, indicating he would soon call Ukrainian President Volodymyr Zelenskyy and European leaders to apprise them of the talks.

"There are just a very few that are left. Some are not that significant. One is probably the most significant, but we have a very good chance of getting there. We didn't get there, but we have a very good chance of getting there," he added.

Specifics on the deal framework were not immediately available, and it is unclear what "significant" obstacle Trump was referring to when he addressed reporters.

Putin separately said he hopes the "understanding" reached with Trump will open a "path towards peace in Ukraine," describing the talks as "friendly."

"We expect that Kyiv and European capitals will perceive that constructively and that they won't throw a wrench in the works," he said during a brief news conference with Trump. "I agree with President Trump, as he has said today, that naturally, the security of Ukraine should be insured as well. Naturally, we're prepared to work on that."

Putin also voiced support for improving ties with the US, saying, "It is clear that the US and Russian investment and business cooperation has tremendous potential."

"Russia and the US can offer each other so much in trade, digital, high tech and in space exploration; we see that arctic cooperation is also very possible," he said.

Neither leader took questions from reporters.