Former Democratic presidential nominee Hillary Clinton has forfeited her government security clearance and requested the cancellation of clearances granted to five aides.

Senate Judiciary Chairman Chuck Grassley released a letter from the State Department on Friday, confirming that Clinton, former chief of staff Cheryl Mills and four other unnamed staffers lost their access to state secrets on September 20.

Grassley asked State more than a year ago to investigate whether Clinton and her aides still held security clearances.

President Donald Trump has long criticized Clinton for operating an unsecured secret home-brew email server during the years she was America's top diplomat. She used it exclusively for emails, both personal and official, while she was an Obama administration official.

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Former Democratic presidential nominee Hillary Clinton has forfeited her government security clearance and requested the cancellation of clearances granted to five aides

President Donald Trump has long complained about security risks posed by an unsecured secret email server Clinton used for all her digital correspondence while she was secretary of state

Trump revoked former CIA director John Brennan's clearance over the summer. The White House said then that the president was reviewing clearances of other top officials, but Clinton's name was not on a list the White House released.

The list included former FBI director James Comey, former CIA director Michael Hayden, former national security adviser Susan Rice and former deputy FBI directorAndrew McCabe.

The letter to Grassley disclosed that Mills and Clinton's other aides 'had been granted access to classified information through a request made by Secretary Clinton designating them as researchers.'

Former State Department Chief of Staff Cheryl Mills is among those Clinton aides who had their clearances removed

The letter to Grassley disclosed that Mills and Clinton's other aides 'had been granted access to classified information through a request made by Secretary Clinton designating them as researchers'

Clinton penned a book that was released in 2017 called What Happened and promoted it in a national and international book tour.

It was revealed in recent days she plans to conduct a speaking tour alongside her husband.

Clinton's August 30 request came just days after President Trump revoked former CIA Director John Brennan's security clearance.

'Mr. Brennan has a history that calls into question his objectivity and credibility,' said White House press secretary Sarah Sanders in announcing the decision.

Brennan had become a harsh critic of Trump's, and critics took the move as an effort to chill opposition as Trump struck back at those involved in the early days of the Russia probe he terms a 'witch hunt.'