NBC News issued an apology Tuesday for the way it handled the broadcasting of the 911 conversation between George Zimmerman and a police dispatcher in the Trayvon Martin case.

Following reports that NBC aired audio of the call was edited in a way that implied Zimmerman was racist, the network launched an internal investigation.

"During our investigation it became evident that there was an error made in the production process that we deeply regret. We will be taking the necessary steps to prevent this from happening in the future and apologize to our viewers," the network said in a statement cited by The Washington Post.

Zimmerman, a volunteer neighborhood watch leader, admits shooting and killing Martin one night in February, but he has said the shooting was in self-defense and justified under the state's "Stand Your Ground" law. He also said Martin attacked him, but that and other details of the case remain in question, as authorities continue to investigate whether to charge Zimmerman.

NBC's "Today" show ran the edited audio of Zimmerman's phone call to a police dispatcher, seeming to show Zimmerman saying, "This guy looks like he's up to no good … he looks black."

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A transcript of the complete 911 call shows that Zimmerman said, "This guy looks like he's up to no good. Or he's on drugs or something. It's raining and he's just walking around, looking about."

The 911 officer responded saying, "OK, and this guy — is he black, white or Hispanic?"

"He looks black," Zimmerman said.

The abridged conversation between Zimmerman and the dispatcher that NBC ran on March 27 has been blasted by media watchdog groups as misleading. Critics have said the edited version was made to suggest that Zimmerman targeted Martin because he was black -- an accusation by many that is still under investigation.

The Associated Press contributed to this report.