US President Donald Trump said he believes Russian President Vladimir Putin's repeated denials of having meddled in the 2016 US presidential election, and only "haters and fools" can't see the benefits of a good relationship with Russia.

"Every time he sees me he says, 'I didn't do that,' and I really believe that when he tells me that, he means it," Trump said on Saturday after meeting the Russian leader briefly on the sidelines of the Asia-Pacific Economic Co-operation summit in Vietnam.

Vladimir Putin and Donald Trump talk as they arrive for the family photo session during the Asia-Pacific Economic Co-operation Summit in Danang on Saturday Credit:AP

"I think he is very insulted by it, if you want to know the truth. Don't forget. All he said was he never did that, he didn't do that. I think he is very insulted by it, which is not a good thing for our country," Trump told reporters aboard Air Force One en route to Hanoi.

However, after coming under significant criticism for the comments, including from intelligence agencies and some fellow Republicans, the President later walked back the comments.