Pressure has been building on Trump over the Russia issue since his firing last week of FBI chief James Comey, who had been leading a federal probe into the matter. Photograph: (Reuters)
The move followed a week of turmoil for the White House amid rising demands for an independent probe of alleged Russian efforts to sway the outcome of November's presidential election
The US Justice Department on Wednesday appointed former FBI Director Robert Mueller as special counsel to investigate possible collusion between President Donald Trump's 2016 campaign team and Russia as well as alleged Russian interference in the US election.
The move followed a week of turmoil for the White House amid rising demands for an independent probe of alleged Russian efforts to sway the outcome of November's presidential election in favour of Trump and against Democrat Hillary Clinton.
Pressure has been building on Trump since his firing last week of James Comey, chief of the Federal Bureau of Investigation, who had been leading a federal probe into the matter.
US intelligence agencies said earlier this year that Russia interfered in the US election. Moscow has dismissed the allegations, and the Trump team has denied any collusion with Russia.
"My decision (to appoint a special counsel) is not the finding that crimes have been committed or that any prosecution is warranted. I have made no such determination," Deputy Attorney General Rod Rosenstein said in a statement.
"I determined that a special counsel is necessary in order for the American people to have full confidence in the outcome," he said.
The controversy has caused an uproar in Washington and on Wall Street where the S&P 500 and the Dow had their biggest one-day declines since September as investor hopes for tax cuts and other pro-business policies faded amid the political tumult.
Democrats in Congress and some of Trump's fellow Republicans had called for an independent investigation.
US Representative Elijah Cummings, senior Democrat on the House of Representatives oversight committee, applauded Rosenstein's action, saying: "I think he made a solid choice in Mr. Mueller, and I commend him for putting our country and justice system first."