Dan Nainan (Helayne Seidman For The Washington Post)

This is an expanded and updated version of a story first published at 12:17 a.m. Thursday — includes news of charges against Nainan and more witness accounts.

A Washington journalist was punched in the face late Wednesday, apparently over some wisecracks he made over Twitter — which doesn’t happen nearly as often as you might think in this town.

The incident — which culminated in the arrest of stand-up comedian Dan Nainan — occurred at the Improv, a Dupont Circle comedy club where Nainan was performing and writer Josh Rogin was in the audience.

Rogin, a foreign-policy scribe for the Daily Beast, tweeted some mildly tart criticism of Nainan’s routine:

Minutes later, Nainan approached the writer at his table in the back, Rogin said. “He said, ‘Are you Josh Rogin?’ I said yes, and he punched me in the jaw.”

Nainan also pushed him, Rogin said, then briefly walked away – only to return to take two more swings. (One connected, Rogin said.) Other witnesses, including National Journal reporter Elahe Izadi, who had been sitting near Nainan, confirmed the encounter. A U.S. News reporter also published her first-hand observations of the incident.

Bouncers removed Nainan from the room, and police arrived to interview both men separately. According to the arrest report, police charged Nainan, 52, with simple assault.

The incident became an immediate social-media sensation, with Rogin himself possibly the first to tweet the news. The room was filled with Twitter-happy Beltway denizens who had gathered for the semi-annual “Funniest Celebrity in Washington” contest, which — despite a questionable record of charity fundraising (update, 9/30: “Funniest Celebrity” giving record remains weak) — has remained a favorite with media and policy types. Tax advocate Grover Norquist, CNN anchor Candy Crowley and columnist Clarence Page were among the “celebrities” doing stand-up shtick – with Nainan, a veteran comic popular on the corporate circuit, brought in to rev the crowd up with a professional routine.

A witness cited in the arrest report, videographer Matt Buerhaus, told our colleague Peter Hermann the brief and “bizarre” incident went down much as Rogin described it, with the writer taking no action other than to try to protect himself from Nainan’s blows. Buerhaus added, though, that he thought Rogin’s live-tweeted review was off-base: Nainan’s performance “was funny and fresh to me.”

In an e-mail Thursday morning, Nainan denied the accounts of other witnesses and the police report and said he was only standing up for other comedians on stage that night.

Rogin, 34, said he was surprised by the alleged attack. “I didn’t think I was being too harsh with him – he’s a professional comedian and I was being a professional journalist.”

Also: “My face hurts.”

Well, as they say: Other than that, Mrs. Lincoln, how did you enjoy the show?

“I felt that it was an unfortunate distraction,” Rogin said, “from an otherwise good event.”