Fox News host Megyn Kelly riled former Florida Gov. Jeb Bush on Thursday night when she pressed the Republican presidential candidate about his efforts to fend off criticism of his brother’s handling of 9/11, even as he slammed Hillary Clinton for the Benghazi attacks.

Kelly asked whether it’s a double standard to shut down questions about President George W. Bush’s handling of the Sept. 11, 2001 terror attacks while saying Clinton bears responsibility for the 2012 Benghazi attacks that claimed four American lives.

“Not at all because if someone had evidence that there was a pending attack, there was – a lot of investigations after 9/11, if there was tangible evidence that there was an attack that was pending and no one acted, of course there would have been criticism, but that’s not the case,” Bush responded.

The Fox host fired back, saying Bush’s GOP rival Donald Trump has argued then-CIA director George Tenet did warn the older Bush brother of the threats posed by Osama bin Laden and al-Qaeda.

Jeb started to lose his cool.

“Trump doesn’t know what he’s talking about. Trump doesn’t know what he is talking about!” Bush said. “He doesn’t know anything about this. And he doesn’t know what he’s talking about.”

Bush went on to say there were “massive investigations” after 9/11 but conceded “we let our safeguards down.”

“I mean under the Clinton administration, it was the law enforcement operation. But in the case of Benghazi, there were clear signs that this consulate was at risk. It had already been attacked. It was 9/11, there wasn’t the security,” Bush told Kelly.

The Florida Republican again criticized Clinton for her 11-hour Benghazi testimony in the House, and said while he didn’t watch much of the proceedings, Clinton won’t accept responsibility for the attacks and continues “leading from behind” in Libya.

Watch the full exchange, via Fox News: