Donald Trump said Sunday he backs US intelligence agencies who concluded Russia meddled in the 2016 US presidential election, but repeated his trust in the sincerity of Russian President Vladimir Putin's personal denials.

"As to whether or not I believe it or not, I'm with our agencies. I believe in our... intelligence agencies," Trump told reporters in Hanoi. 

US intelligence chiefs have told congress Russia meddled in the election, but Putin has repeatedly denied any Russian involvement