The United States Justice Department has appointed a former FBI boss, Robert Mueller, as the special counsel to oversee an inquiry into Russia’s alleged meddling in the election and any Trump campaign ties.

The Deputy Attorney General Rod Rosenstein says it is in the public interest to have an outsider.

The appointment was widely endorsed by politicians from both sides as calls for a special investigation had mounted since President Donald Trump fired James Comey from his role as FBI director last week.

But the announcement apparently took the White House by surprise, with Mr Trump only being informed of it after the deputy attorney general had signed the order.

The FBI and congress are looking into potential links between Mr Trump’s campaign team and Russia. U.S. intelligence agencies believe Moscow tried to tip the election in favour of Mr Trump.