Washington DC - Adam Kinzinger, a former member of the congressional committee that investigated the January 6 attacks, hit back at Donald Trump after the president said he was annulling his preemptive pardon.

Trump on Monday said he had deemed pardons issued by his predecessor Joe Biden "VOID, VACANT, AND OF NO FURTHER EFFECT" because they were "done by Autopen."

In an X video, Kinzinger said that the work he and the committee did "embarrassed" Trump, causing the president to become "obsessed."

"Hey Trump – bring it on, dude! You weak, whiney, tiny man," he added.

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Kinzinger also appeared on CNN, saying that Trump was simply trying to sound "tough."

"Bring the charges then, if you really want to do it, because we would crush you in court, and it will make me three times more effective against you," he insisted.

"I'm ready to move on, too... Bring it [on], or be quiet."

Biden issued the pardons for members of the committee to shield them from Trump's repeated promises that he would pursue revenge after winning re-election.

It's unclear if the Republican has the authority to pull his unprecedented move, but on Monday he said he was ready to take the matter to court.