The FBI has opened an investigation into allegations that media mogul Rupert Murdoch's News Corp. sought to hack into the phones of Sept. 11 victims, a law enforcement official said Thursday.

The official spoke Thursday to The Associated Press on condition of anonymity because he was not authorized to speak publicly.

New York City-based News Corp. has been in crisis mode.

A rival newspaper reported last week that the company's News of the World had hacked into the phone of U.K. teenage murder victim Milly Dowler in 2002 and may have impeded a police investigation into the 13-year-old's disappearance.

More possible victims soon emerged: other child murder victims, 2005 London bombing victims, the families of dead soldiers and former Prime Minister Gordon Brown.

The FBI's New York office didn't immediately comment Thursday. There was no immediate response to messages left for News Corp. and the U.S. attorney's office in Manhattan.

On Thursday, Murdoch caved in to pressure from Britain's Parliament as he and his son James first refused, then agreed, to appear next week before lawmakers investigating phone hacking and bribery by employees of their newspaper empire.

Murdoch began his media career in Australia in 1952 after inheriting The News newspaper after the death of his father, and he has built News Corp. into one of the world's biggest media groups. Assets include Fox News, the 20th Century Fox movie studio, The Wall Street Journal, the New York Post and three newspapers in Britain _ down from four with the death of the News of the World.