US President Donald Trump says an agreement with Russian President Vladimir Putin on Syria would save many lives after the two met at a summit of Asia-Pacific leaders.

Key points: Mr Trump and Mr Putin agreed a political solution was needed on Syria

Mr Trump and Mr Putin agreed a political solution was needed on Syria The US President said Mr Putin reiterated that he did not meddle in the recent US presidential elections

The US President said Mr Putin reiterated that he did not meddle in the recent US presidential elections Mr Putin said the alleged Manafort link to Russia was fabricated by Mr Trump's opponents

"We agreed very quickly," Mr Trump told reporters aboard Air Force One as he flew from the Asia-Pacific Economic Cooperation (APEC) meeting in the resort city of Danang to Vietnam's capital Hanoi.

"It's going to save tremendous numbers of lives."

The Kremlin earlier said Mr Trump and Mr Putin had agreed on the sidelines of the APEC summit that a political solution was needed on Syria and that they would continue efforts to fight Islamic State.

"We spoke intermittently during that roundtable. We seem to have a very good feeling for each other and a good relationship considering we don't know each other well," Mr Trump said, adding that he and Mr Putin had two or three very short conversations.

Trump says election distraction is putting lives at stake

Mr Trump said Mr Putin had reiterated that he did not meddle in last year's US presidential elections, which brought Mr Trump to the White House.

"He says he didn't meddle. I asked him again. You can only ask so many times," Mr Trump said.

"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."

Donald Trump said he asked Vladimir Putin about the US election. ( Reuters: Sputnik/Mikhail Klimentyev/Kremlin )

Mr Trump made clear that the issue of Russian meddling in the election hovers over the leaders' relationship — Mr Putin is "insulted" by the accusation, Mr Trump said.

In a blistering partisan attack, Mr Trump accused Democrats of using the election issue to create a barrier between the US and Russia as the nations work on crises in Syria and Ukraine.

He said it was a distraction that was putting lives at stake.

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

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

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.

Putin tells Trump alleged Manafort Russia link fabricated

An alleged link between US President Donald Trump's former campaign manager Paul Manafort and Russia, Mr Putin said, was being fabricated by Mr Trump's opponents as a weapon against Mr Trump.

Reports that Mr Putin's relatives were involved in contacts with the Trump administration were untrue, Mr Putin told a briefing at the end of the APEC summit.

Donald Trump believes the North Korea issue would 'go away a lot faster' if Russia and China helped. ( Jorge Silva: AP )

Meanwhile, Mr Trump said a good relationship with Russia was also important because they could help the US in in North Korea.

"We have a big problem with North Korea and China is helping us," Mr Trump said.

"If Russia helped us in addition to China that problem would go away a lot faster."

Mr Trump said Chinese President Xi Jinping was a good man who "wants to do right," but he wanted Mr Xi to ratchet up more pressure on North Korea.

Reuters/AP