A Twitter war has broken out between CNN host Piers Morgan and journalist and television commentator Touré, who criticized Morgan for being too soft in an interview with George Zimmerman's brother, Rob Zimmerman.

Rob Zimmerman was defending his brother, who says he killed Florida teenager Trayvon Martin last month in self-defense in a case that has brought debates about racism and justice into the spotlight.  

Rob Zimmerman denied reports that his brother, a white and Hispanic neighborhood watchman, chased after Trayvon, a black, unarmed 17-year-old.

The fantasy or mythology that he chased a person is absolutely false, Rob Zimmerman told Morgan on his show Thursday night. He stopped someone from disarming him and shooting him. He didn't pull out a gun and shoot him.

Touré called the comments absurd testimony and accused Rob Zimmerman of trying to poison a future jury & spreading misinformation.

George Zimmerman has not been charged with a crime in Trayvon's killing, but the U.S. Justice Department is looking into the case.

Touré accused Morgan of being too soft on Rob Zimmerman.

Piers did not challenge Robert Zimmerman in the way a professional journalist should, he tweeted.

Morgan responded, Oh Touré, you're such a tedious little twerp.

Touré fired back, Allowing Rob Zimmerman to spout unchallenged lies further poisons a tense moment in American history. Be professional.

The two men continued to trade barbs, with Touré saying Morgan was a pawn when he did Donald Trump's The Apprentice and Morgan calling his feuding partner a bull-dodging rodeo clown.

Morgan also dissed his new rival over his lack of Twitter followers.

ps @Toure - 71k tweets for just 57k followers? Ouch. Ever get the feeling you're doing a LOT of jabbering but nobody's listening? Morgan wrote.

The latest in the feud is that Morgan challenged Touré to come on his show, but there's been no word yet on whether he's accepting the offer.

OK @Toure - we're on. Get to my CNN bureau in NY between 3-5pm ET and we will do this debate on air tonight. Deal?, Morgan said.

After four minutes no response, the CNN host continued, Come on @Toure - everyone's waiting. You man or mouse?