The U.S. State Department has suspended an internal review of whether classified information was properly handled in former Secretary of State Hillary Clinton's emails at the request of the FBI, a spokeswoman said on Friday.

Clinton, the front-runner in the race for the Democratic Party nomination in the Nov. 8 presidential election, has apologized for using a private email server for official business while in office from 2009 to 2013 and said she did nothing wrong. The FBI is investigating the arrangement.

On Jan. 29, the State Department said 22 emails sent or received by Clinton had been upgraded to top secret at U.S. intelligence agency's request and would not be made public as part of the release of thousands of Clinton's emails. It said that none of the emails was marked classified when sent.

At the time, the department also said it would conduct an internal review on whether the information in the emails was classified at the time it passed through Clinton's private account run on a server in her New York home.

The department consulted the FBI about this in February, and in March the law enforcement agency asked the State Department to halt its inquiry.

"The FBI communicated to us that we should follow our standard practice, which is to put our internal review on hold while there is an ongoing law enforcement investigation ," State Department spokeswoman Elizabeth Trudeau told reporters.

"The internal review is on hold, pending completion of the FBI's work," she added." We'll reassess next steps after the FBI's work is complete."

The government forbids handling of classified information, which may or may not be marked that way, outside secure government-controlled channels, and sometimes prosecutes people who remove it from such channels. The government classifies information as top secret if it deems a leak could cause "exceptionally grave damage" to national security.

Two judges have allowed a group suing for Clinton's records to seek sworn testimony from officials. On Tuesday, one judge said there was "evidence of government wrongdoing and bad faith" over the arrangement.