Mueller probe should never have been started: Trump

United States President Donald Trump, in a series of tweets, said that special counsel Robert Mueller's investigation into possible collusion between the Trump campaign and Russia should never have been opened in the first place.

"The Mueller probe should never have been started in that there was no collusion and there was no crime. It was based on fraudulent activities and a Fake Dossier paid for by Crooked Hillary and the DNC, and improperly used in FISA COURT for surveillance of my campaign. WITCH HUNT!" Trump wrote on Twitter.

"The Fake News is beside themselves that McCabe was caught, called out and fired. How many hundreds of thousands of dollars was given to wife's campaign by Crooked H friend, Terry M, who was also under investigation? How many lies? How many leaks? Comey knew it all, and much more!" Trump tweeted.

The tweet came hours after President Trump's lawyer, John Dowd, released a statement calling on Deputy Attorney General Rod Rosenstein, who oversees Mueller's investigation, to shut down the probe.

Earlier on Saturday, Former Federal Bureau of Investigation (FBI) director James Comey hit back at Trump, saying that Americans can judge for themselves who is honourable in the government.

Hours after FBI Deputy Director Andrew McCabe was sacked, Comey tweeted, "Mr. President, the American people will hear my story very soon. And they can judge for themselves who is honorable and who is not," Comey tweeted on Saturday."

Earlier on Saturday, the US Justice Department dismissed McCabe on the grounds of lying to the investigators, reviewing the probe of former US Secretary of State Hillary Clinton's email server case.