Rudy Giuliani and John Bolton are feuding with metaphorical explosives

Rudy Giuliani is hitting back at former National Security Adviser John Bolton with his own explosive comparison.

Fiona Hill, President Trump's former top Russia adviser, testified Monday that Bolton expressed concern about Giuliani's effort to get Ukraine to investigate Democrats by comparing him to a "hand grenade who's going to blow everybody up," The New York Times reports.

An angry Giuliani fired back Tuesday with a real "I know you are, but what am I" type of response, comparing Bolton himself to an explosive.

"I'm very disappointed that his bitterness drives him to attack a friend falsely," Giuliani said of Bolton, NBC News reports. "It's really ironic that John Bolton is calling anyone else a hand grenade. When John is described by many as an atomic bomb."

Giuliani further slammed Bolton while speaking to New York magazine's Olivia Nuzzi, saying he's "disappointed" and Bolton's comparison is "almost like projection." Though Bolton didn't make his comment publicly and it instead came by way of an aide's testimony, considering he's got a book on the way and had promised to have his "say in due course," this could be the shape of things to come.