LOS ANGELES — Michael Richards said yesterday that he spewed racial epithets during a stand-up comedy routine because he lost his cool while being heckled and not because he’s a bigot.

“For me to be at a comedy club and flip out and say this crap, I’m deeply, deeply sorry,” the former “Seinfeld” costar said during a satellite appearance for David Letterman’s “Late Show.”

“I’m not a racist. That’s what’s so insane about this,” Mr. Richards said, his tone becoming angry and frustrated as he defended himself. A clip from the show played on CBS before “Late Show” aired last night.

Mr. Richards described himself as going into “a rage” over the two audience members who interrupted his act Friday at the Laugh Factory in West Hollywood. Mr. Richards responded to the black hecklers with repeated use of the “n word” and profanities.

Jerry Seinfeld, who had issued a statement saying he was “sick over this horrible, horrible mistake” and calling it offensive, was scheduled as a Letterman guest yesterday. He encouraged Mr. Richards to make a satellite appearance to talk about the incident, a CBS publicist said.

Mr. Richards, 57, who played Seinfeld’s eccentric neighbor Kramer on the hit 1989–98 sitcom and whose major credit since was a failed 2000 comedy, hadn’t spoken publicly about his remarks before “Late Show.” Calls to his representatives were not returned yesterday.

His onstage remarks were condemned by industry colleagues. Comedian Paul Rodriguez, who was at the Laugh Factory during Mr. Richards’s performance, said he was shocked.