Trump calls US-Russia probe a 'witch hunt' as special prosecutor is named

US president Donald Trump has lashed out at the appointment of a special counsel to investigate possible links between his team and Russia.

Deputy Attorney General Rod Rosenstein on Wednesday appointed former FBI chief Robert Mueller to lead the probe.

In a series of tweets on Thursday, President Trump described the move as a “witch hunt”.

“This is the single greatest witch hunt of a politician in American history!” he tweeted, also complaining that Hillary Clinton and President Obama weren’t investigated by a special counsel.

“With all of the illegal acts that took place in the Clinton campaign & Obama Administration, there was never a special counsel appointed!” he tweeted.

Trump’s latest troubles began when he fired FBI chief James Comey, who had earlier confirmed he was investigating the claims of collusion between Russia and Trump’s team.

“You can start a special investigation that’s more narrow and the further you go, the more people you talk to and the more documents that you obtain, then it becomes broader and I think that that may be the fear of many in the administration tonight,” said Jessica Levinson, a Law professor at the Loyola Law School.

The appointment of the Special Counsel comes just as a memo from the fired FBI director surfaced indicating that the president had asked him to end an investigation of former National Security Adviser, Michael Flynn.