James Comey fired back this week at Hillary Clinton after the former secretary of state cited the Justice Department inspector general report on her email case to challenge the premise of the investigation itself.

Clinton did so in a terse, snarky tweet following the release of the nearly 600-page report, which accused the former FBI director of defying the chain of command during the email probe. It also said he, too, used a personal email account for some government business.

“But my emails,” Clinton tweeted, in response to a reporter tweet about Comey’s use of a “gmail” account -- a slap at the outrage over her private email server and the FBI probe itself.

But during an interview in Berlin this week, Comey was asked whether he would apologize to Clinton -- and refused. He stressed the difference between his personal email use, which involved unclassified information, and hers and said she still doesn't understand why she was investigated.

COMEY USED PERSONAL EMAIL TO CONDUCT FBI BUSINESS, WATCHDOG REPORT FINDS

“No. And here’s why. I don’t want to criticize her, but it shows me that even at this late date, she doesn’t understand what the investigation in her case was about,” Comey said during an interview with German newspaper Die Zeit.

“It was not about her use of a personal email system, and she didn’t get that during the investigation, because she used to say ‘Colin Powell when he was secretary of state used AOL,’ that was not what it was about,” Comey explained. “It was about communicating about classified topics on that system when those topics have to be done on a classified system.”

He added: “Which she never did. It would have been a problem if she was using AOL, or gmail, or Clinton.com—or the State Department’s [unclassified] system.”

DOJ Inspector General Michael Horowitz found that Comey used a personal email account to “conduct unclassified FBI business,” which he found was “inconsistent with Department policy.” Horowitz cited what he called “the absence of exigent circumstances the frequency with which the use of personal email occurred.”

Comey defended his use of a personal email account—but said he understood why Horowitz put it in the report.

“What I would do, is when I had to write speeches—I would write my own speeches—I would type them at home and then gmail them into my government account,” Comey explained. “Or, if I still had to work on the draft, I would send it home so I could work on it on my laptop.”

“I was not talking about anything remotely classified and the inspector general didn’t say that as well,” Comey said. “But I get why the tweet, and I get why people are focused on it, but it’s a totally different thing.”

Comey first broke his silence on the inspector general report last week in an op-ed for the New York Times.

The former FBI boss, separately, is facing IG scrutiny over his handling of classified information in memos memorializing conversations with President Trump.