The Justice Department said Wednesday it planned to name a special counsel in the investigation into Russia’s meddling into the 2016 presidential election.

Deputy Attorney General Rod Rosenstein said former FBI Director Robert Mueller will oversee the probe.

“Based upon the unique circumstances, the public interest requires me to place this investigation under the authority of a person who exercises a degree of independence from the normal chain of command,” Rosenstein said in a statement.

“A special counsel is necessary in order for the American people to have full confidence in the outcome. Our nation is grounded on the rule of law, and the Public must be assured that government officials administer the law fairly.”

The appointment comes as Attorney General Jeff Sessions has come under increasing pressure from Capitol Hill to launch an independent investigation into the matter.

Mueller, a former prosecutor and US Marine, served as FBI director under Presidents George W. Bush and Barack Obama.

As special counsel, Mueller has all the powers of a federal prosecutor, including subpoena power. However, he will answer to Rosenstein.