The United States is looking into allegations that the electronic book industry has violated antitrust law, a top Justice Department official said on Wednesday.

In an oversight hearing, the Justice Department's top antitrust official Sharis Pozen, in an roundup of her division's work, said: We are also investigating the electronic book industry along with the European Commission and with states attorneys general.

In Brussels, the European Commission said Tuesday that it had opened an investigation into whether e-book publishers owned by Lagardere, Pearson Plc

, News Corp and two other firms fixed prices with Apple Inc , blocking rivals and hurting consumers.

It identified the publishers as French media-to-aerospace group Lagardere's Hachette Livre unit, News Corp's Harper Collins, CBS Corp's Simon & Schuster, Pearson's Penguin and Verlagsgruppe Georg von Holzbrinck, which owns Macmillan in Germany.

Publishers adopted the agency model last year when Apple launched the iPad, allowing publishers to set the price of e-books. In turn, they would share revenue with the retailer.

In the past, publishers would sell e-books on a wholesale model for 50 percent of the retail price.

Pozen, who is an acting chief of the antitrust division, noted that the investigation, along with other actions that the division has taken, without giving any details.

The division is fighting AT&T's plan to buy T-Mobile USA from Deutsche Telekom , has sued American Express regarding merchant fees, and is conducting a range of price-fixing investigations.

(Reporting by Jasmin Melvin and Diane Bartz; Editing by Richard Chang)