NORFOLK, Va. — A Somali pirate has been sentenced to life in prison for his role in attacking a U.S. Navy ship.

Federal prosecutors said Wednesday that 31-year-old Mohamed Farah was among seven pirates who tried to commandeer the USS Ashland in 2010.

The men had mistaken the Ashland for a cargo vessel in the Gulf of Aden. After the pirates opened fire, U.S. sailors destroyed their skiff and killed one pirate.

The sailors rescued the surviving pirates. Farah and the remaining attackers were prosecuted in federal court in Norfolk and sentenced to various jail terms.

Farah's attorney, Jason Dunn, told The Associated Press in an email that the sentence was excessive but unavoidable.

The mandatory sentence for piracy has been life in prison since 1909. Before that, the mandatory punishment was death.