(AP) -- The State Department is reopening an internal investigation of possible mishandling of classified information by Hillary Clinton and top aides, officials told The Associated Press on Thursday.

Although the former secretary of state's closest confidants have left the agency, they could still face punishment. The most serious is the loss of security clearances, which could complicate her aides' hopes of securing top positions on her national security team if she becomes president.

The State Department started its review in January after declaring 22 emails from Clinton's private server to be "top secret." It was suspended in April so as not to interfere with the FBI's inquiry. State Department spokesman John Kirby said the probe is restarting after the Justice Department's announcement Wednesday that it won't bring any criminal charges.

"We will aim to be as expeditious as possible, but we will not put artificial deadlines on the process," Kirby said. "Our goal will be to be as transparent as possible about our results, while complying with our various legal obligations."

Kirby wouldn't say anything more about the precise information officials are evaluating. But when the probe was launched almost six months ago, officials said it pertained particularly to a set of emails that were upgraded to one of the nation's highest classification levels. One question they said they were investigating was whether any of the emails were classified at the time of transmission.

Additionally Thursday, Republican lawmakers said they would now ask the FBI to investigate whether Clinton lied to the committee. That announcement came in a testy hearing with FBI Director James Comey, who defended the government's decision not to prosecute Clinton over her private email setup.

Clinton was secretary of state until early 2013. Most of her top advisers left shortly thereafter.

But Kirby said this week former officials can still face punishment. Options range from counseling and warnings to the revocation of an individual's security clearance.

Beyond the Democratic front-runner, the probe is will most likely examine confidants Cheryl Mills, Jake Sullivan and Huma Abedin -- who wrote many of the emails to their boss that the various investigations have focused on. Mills, Clinton's chief of staff at the State Department, has been viewed as a possibility for the same job in the White House. There is speculation that Sullivan, Clinton's former policy chief, could be national security adviser.

"There could be repercussions," Kirby told reporters Wednesday, saying infractions identified would be kept on file. If someone's security clearance is taken away, he said it would have an effect "assuming that individual still needed the clearance to work in another federal agency or something like that."

The State Department says it won't identify former officials that still hold security clearances. But in an email Fox News made public earlier this year, the department described Mills as still holding a valid clearance.