Washington: US President Donald Trump, grappling with a torrent of criticism over his performance at a Helsinki summit with Russian President Vladimir Putin, said he misspoke at their joint news conference, marking a rare reversal from comments just a day earlier.

Even so, Trump added that, while he accepts the conclusion by US intelligence agencies that Russia interfered in the US presidential election, the meddling "could be other people also".

Trump has come under unprecedented criticism from Democrats and Republicans for statements he made in Helsinki that sided with Putin over the US intelligence community.

Standing alongside Putin at the news conference, Trump was asked if he believed US intelligence agencies' conclusions on election meddling or Putin's claims that Russia was not to blame.