US Attorney General William Barr on Thursday said that the investigation by special counsel Robert Mueller found "no evidence" of collusion between the Trump campaign and the Russian government during the 2016 US presidential elections.

Addressing the media at the Department of Justice here, Barr said Mueller investigated a number of links or contacts between Trump Campaign officials and individuals connected with the Russian government.

"After reviewing those contacts, the special counsel did not find any conspiracy to violate US law involving Russia-linked persons and any persons associated with the Trump campaign," Barr said.

He, however, said the Russian government sought to interfere in US election process.

Barr was speaking on Special Counsel Mueller's final 400-page report on Russian meddling in the 2016 election.

Earlier Thursday, President Donald Trump said the probe was "Greatest Political Hoax of all time!"

"Crimes were committed by Crooked, Dirty Cops and DNC/The Democrats," tweeted Trump, who refers his election rival and former secretary of state Hillary Clinton as "Crooked".