Trump declined to say whether he believed Putin, but made clear he's not interested in dwelling on the issue.
"He said he absolutely did not meddle in our election. He did not do what they are saying he did," Trump said of Putin, speaking with reporters aboard Air Force One as he travelled to Hanoi, the second-last stop of his Asia trip.
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"Every time he sees me, he said: 'I didn't do that.' And I believe, I really believe that when he tells me that he means it," Trump said, noting that Putin is "very insulted" by the accusation. Trump called the accusation an "artificial barrier" erected by Democrats - once again casting doubt on the US.intelligence community's conclusion that Russia did try to interfere in the election to help Trump win.
Trump and Putin did not have a formal meeting while they were in Vietnam for the Asia-Pacific Economic Cooperation summit, but the two spoke informally several times on the event's sidelines and reached an agreement on a number of principles for the future of war-torn Syria.
But Trump made it clear that the issue of Russian meddling in the election hovers over the leaders' relationship and said it jeopardised their ability to work together on issues including North Korea's escalating nuclear programme and the deadly conflict in Syria.
"Having a good relationship with Russia's a great, great thing. And this artificial Democratic hit job gets in the way," Trump told reporters. "People will die because of it".
Trump danced around the question of whether he believed Putin's denials, telling reporters that pressing the issue would have accomplished little.
"Well, look, I can't stand there and argue with him," he added later.
"I'd rather have him get out of Syria, to be honest with you. I'd rather have him, you know, work with him on the Ukraine than standing and arguing about whether or not - cause that whole thing was set up by the Democrats".
Trump's suggestion that he may believe Putin over his own nation's intelligence community is certain to re-ignite the firestorm over the issue of election meddling. Meanwhile, a special counsel investigation of potential collusion between Moscow and Trump campaign aides so far has resulted in two indictments for financial and other crimes unrelated to the campaign, as well as a guilty plea. Congressional committees have also been interviewing campaign and White House staff.
The Kremlin earlier on Saturday issued a statement saying the leaders had reached agreement on a number of principles for the future of civil war-torn Syria now that the Islamic State group has largely been pushed out.
Among the agreements' key points, according to the Russians, were an affirmation of de-escalation zones; a system to prevent dangerous incidents between American and Russian forces and a commitment to a peaceful solution governed by a Geneva peace process.
Trump will be attending a state dinner in Hanoi on Saturday night. On Sunday, he'll meet the country's president and prime minister before heading to the Philippines, his last stop.