President Donald Trump said Saturday that Russia's Vladimir Putin again denied interfering in the 2016 U.S. elections. But Trump declined to say whether he believed the Russian leader.

"He says he didn't meddle. I asked him again. You can only ask so many times," Trump told reporters aboard Air Force One on the trip to Hanoi, Vietnam. "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 and Putin did not have a formal meeting while they were in Vietnam for an economic summit, but the two spoke informally several times and reached agreement on a number of principles for the future of war-torn Syria. But Trump made clear that the issue of Russian meddling in the election hovers over the leaders' relationship — Putin is "insulted" by the accusation, Trump said. In a blistering partisan attack, Trump accused Democrats of using the election issue to create a barrier between the U.S. and Russia as the nations work on crises in Syria and Ukraine.

"Having a good relationship with Russia's a great, great thing. And this artificial Democratic hit job gets in the way," Trump told reporters, once again casting doubt on the U.S. intelligence community's conclusion that Russia did try to interfere in the election. "People will die because of it."

Trump's suggestion that he may believe Putin over his own nation's intelligence community is certain to re-ignite the firestorm over the 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.

Trump said the probe into the election hacking was a "fake barrier" placed by Democrats that was hurting the United States' ability to have a relationship with Russia, a distraction that was putting lives at stake.

The Kremlin issued a statement Saturday saying that the leaders met during the Asia-Pacific Economic Cooperation conference in Denang and reached agreement on a number of principles for the future of the civil war-torn country 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.

The Kremlin quickly promoted the agreement as the White House stayed silent. Trump told reporters that the deal was reached "very quickly" and that it would save a number of lives. And he praised his relationship with Putin, saying "We seem to have a very good feeling for each other and a good relationship, considering we don't know each other well."

Snippets of video of conference events have shown Trump and Putin shaking hands and chatting, including during the world leaders' traditional group photo. The two walked together down a path to the photo site, conversing amiably, with Trump punctuating his thoughts with hand gestures and Putin smiling.

Journalists traveling with Trump were not granted access to any of the APEC events he participated in in the picturesque tropical seaside city.

White House officials worked quietly behind the scenes negotiating with the Kremlin over a formal meeting. The Russians raised expectations for such a session and Trump told reporters aboard Air Force One en route to Asia that it was "expected we'll meet with Putin" to discuss issues including ramping up pressure on North Korea to halt its nuclear and ballistic weapons program.As speculation built, the two sides tried to craft the framework of a deal on the future of Syria that Trump and Putin could announce in a formal bilateral meeting, according to two administration officials not authorized to speak publicly about private discussions.

Though North Korea and the Ukraine had been discussed, the two sides focused on trying to strike an agreement about a path to resolve Syria's civil war once the Islamic State group is defeated, according to officials. But the talks stalled and, minutes before Air Force One touched down in Vietnam, White House press secretary Sarah Huckabee Sanders told reporters the meeting was off.

Putin and Trump crossed paths several times during the conference.

The two men, each wearing traditional blue Vietnamese shifts, shook hands and greeted one another as they stood side-by-side for the group photo of world leaders.

On Saturday, they were also seen shaking hands and speaking briefly during one meeting, according to a Fox News videographer who was the only American journalist allowed into the room. Trump and Putin were also seen chatting, with plenty of hand gestures from Trump, as they walked side by side to a dramatic vista overlooking the South China Sea for another group picture.

Trump who is on a lengthy Asia trip, attended meetings and a lunch Saturday before heading to the capital city of Hanoi for a state visit.