Donald Trump said on Sunday he backed United States intelligence agencies who concluded that Russia meddled in the 2016 US presidential election, but repeated his trust in the sincerity of Vladimir Putin’s denials and slammed critics of his relationship with the Russian leader.

Key former Trump aides are under US investigation for possible collaboration with the Kremlin and the issue of whether Moscow interfered with last year’s vote has overshadowed the tail end of the president’s on-going Asia tour.

Trump returned to the subject in an early morning Twitter storm, which also saw him take a sarcastic dig at North Korea’s “short and fat” leader Kim Jong-Un.

Addressing a press conference in Hanoi, Trump was asked to clarify comments he had made on Air Force One the day before about Putin’s insistence that Moscow had never tried to affect the outcome of the US vote.

“I believe he feels he and Russia did not meddle in the election,” Trump said.

As to whether or not I believe it or not, I’m with our agencies. I believe in our intelligence agencies,” he added.

In May, US intelligence chiefs told Congress they agreed with their analysts’ conclusion that Russia had interfered in the election.

CIA director Mike Pompeo, who was appointed by Trump, said he still believed in that evaluation in a statement to CNN.

In his barrage of tweets earlier Sunday, Trump slammed “haters” who questioned his efforts to improve ties with Russia.

“There’s always playing politics, bad for our country. I want to solve North Korea, Syria, Ukraine, terrorism, and Russia can greatly help!” he said.

Trump was in Hanoi for a brisk visit with Vietnam’s top communist leaders to drum up trade deals and seek further support on containing North Korea’s nuclear weapons ambitions, which have been a dominant theme on each leg of his Asia tour.