US President Donald Trump has issued an angry response after a TV interview on Sunday alleged that officials had held discussions to have him removed.
Mr Trump tweeted of “illegal and treasonous” behaviour and an “illegal coup attempt”.
In the interview, ex-acting FBI chief Andrew McCabe said talks had been held in 2017 about invoking a clause that can remove a president deemed unfit.
The Senate Judiciary Committee chairman has vowed to investigate the claims.
Lindsey Graham said the claims were an “attempted bureaucratic coup”.
In a series of tweets on Monday morning, he condemned “so many lies by now disgraced acting FBI Director Andrew McCabe. He was fired for lying and now his story gets even more deranged.
“He and Rod Rosenstein, who was hired by [then Attorney General] Jeff Sessions (another beauty), look like they were planning a very illegal act, and got caught.”