Gay groups are outraged at allegations that 30 Rock star Tracy Morgan launched into an anti-gay rant during a stand-up comedy set in Nashville.

The allegations surfaced on the Facebook page of Kevin Rogers.

Rogers claims the 42-year-old Morgan said during his June 4 routine that he would stab his son to death if he found out he was gay.

“He said if his son was gay he better come home and talk to him like a man and not [he mimicked a gay, high pitched voice] or he would pull out a knife and stab that little N (one word I refuse to use) to death,” Rogers wrote.

Morgan “informed us that the gays needed to quit being pussies and not be whining about something as insignificant as bullying. He mentioned that gay was something kids learn from the media and programming, and that bullied kids should just bust some ass and beat those other little f*ckers that bully them, not whine about it. … Tracy then said he didn't fucking care if he pissed off some gays, because if they can take a f*cking dick up their ass … they can take a f*cking joke.”

Evan Hurst of the gay rights group Truth Wins Out called on NBC to investigate the claims.

“If Tracy Morgan indeed did say these things, he need to respond immediately with either an explanation or a contrite apology,” Hurst said in a statement.

“Tracy Morgan has worked under 30 Rock writer and producer Tina Fey since 2006. Ms Fey has a long record of supporting LGBT causes, and so we would ask her to respond to these allegations as well.”

“I went to Tracy Morgan's show to laugh and enjoy someone who I thought was a brilliant comic,” Rogers, who is gay, added. “I left feeling like the joke was on me.”