AT&T confirmed on 28 April that it has fired Aaron Slator, the president of its U-verse business, amid a $100m (£65m, €91m) discrimination lawsuit that alleges Slator used his work phone to send racially offensive images.

The Associated Press quoted the second-largest US mobile-phone carrier as saying: "There is no place for demeaning behavior within AT&T and we regret the action was not taken earlier."

The images in question were found on Slator's phone by an assistant who was asked to transfer data to a new phone, according to the lawsuit filed by Knoyme King, a 50-year-old black woman who worked for Slator.

The lawsuit said one of the images, apparently of an African child dancing with the caption "It's Friday ..." followed by a term offensive to African Americans, had been sent in a text describing it as an "oldie but a goodie".

King's lawyer, Skip Miller, told AP on 28 April that the lawsuit will continue. He said AT&T failed to take action earlier, despite the issue being brought to the attention of its human resources department and its board of directors.

Miller said the lawsuit contends that King was passed over for promotions and given inferior raises because of her race, that she was mistreated and that attempts were made to have her leave the firm. King has worked 30 years for AT&T and is still employed there.

The lawsuit, filed in the Los Angeles Superior Court on 27 April, names as defendants Slator, the Dallas-based company, CEO Randall Stephenson, other executives and board member Joyce Roche.

Slator was president of content and advertising sales, managing the firm's multibillion-dollar budget for content acquisition that is consumed by subscribers of AT&T's U-verse TV service.