The State Department slammed former United Nations envoy John Bolton over his suggestion that Secretary of State Hillary Rodham Clinton falsely claimed a concussion to avoid a potentially embarrassing appearance before Congress to explain the deadly terrorist attack on the U.S. mission in Benghazi, Libya.

In an appearance on Fox News, Bolton said that Clinton’s claim that she had fainted because of the flu, hitting her head and suffering a concussion, was what foreign service officers call a “diplomatic illness,” intended to free a diplomat from an unpleasant duty. Clinton was supposed to appear before congressional foreign affairs committees on Thursday to respond to questions about whether security failures opened the way for the Sept. 11 attack.

“This is a diplomatic illness to beat the band,” said Bolton, who served during the George W. Bush administration. “I mean, I hope it’s nothing serious. But this was revealed in a way that I think was not transparent and I think there is an obligation here.”