WASHINGTON » Pirates attacked a commercial ship near the coast of Nigeria and kidnapped two U.S. mariners, a U.S. defense official said today.

The captain and an engineer were taken away from the offshore supply vessel during the Wednesday afternoon attack in international waters of the Gulf of Guinea, said the official who spoke on condition of anonymity because the official wasn’t authorized to publicly discuss the information.

The pair were kidnapped from the U.S.-flagged vessel named C-Retriever, a 222-foot ship owned by Edison Chouest Offshore of Louisiana, the official said.

The vessel and 11 other members of the crew were released, the official said.

Nigerian Navy Capt. Kabir Aliyu confirmed that there was an attack.

It was unclear whether a ransom demand had been made.

The U.S. defense official said the U.S. Navy is monitoring the situation and that the closest military vessel is a Dutch Navy ship in the Gulf of Guinea with 90 U.S. Marines aboard as part of an Africa training mission.

Associated Press writers Michelle Faul in Lagos, Nigeria, and Lolita C. Baldor in Washington contributed to this report.