Washington, Jul 8 (IANS): US House Republicans accused the FBI of using a "double standard" to investigate Hillary Clinton's usage of several private e-mail servers for official business when she was secretary of state from 2009-2013.

House Oversight and Government Reform Committee Chairman Jason Chaffetz on Thursday said he believed that there was a legitimate concern of a double standard, with Clinton being treated differently by the US Department of Justice than regular citizens, EFE news reported.

Chaffetz said he was confused on Tuesday when Federal Bureau of Investigation (FBI) Director James Comey asked the Justice Department that not to recommend any charges to be filed against Clinton, despite the evidence that she and her staffers were "extremely careless" in their handling of certain classified information.

Chaffetz said that if a regular person had done what Clinton was suspected of doing, they would have been arrested.

In the face of the criticism, the FBI chief said that his agency's investigation was apolitical and professional with a team reviewing some 30,000 e-mails sent and received via private servers that Clinton had used both inside and outside the US.

During the tense hearing, Comey acknowledged that those 30,000 e-mails contained three messages that had classified information in them.

Comey said that he did not think that any "reasonable prosecutor" would file charges in this case, adding that he saw evidence of great "carelessness" but there was insufficient evidence to establish that Clinton or her staffers had discussed classified information by e-mail or knew that what they were doing was against the law.

During the hearing, Chaffetz, one of the most influential Republicans in the House, said that he would formally ask Congress to investigate whether Clinton lied when she was questioned for over three hours last on July 2 at the FBI headquarters.

Republican Senate Majority Leader Mitch McConnell on Wednesday asked the FBI to reveal the content of the conversation its agents had with Clinton and on Thursday Republican lawmakers insisted on that point.

Judicial proceedings in the case were officially ended on Wednesday after Attorney General Loretta Lynch confirmed that the Justice Department would not file charges against the former first lady as per the FBI's recommendation.