RICHMOND, Va. (AP) — Attorneys for six Somali nationals accused of attacking a U.S. Navy ship off the coast of Africa are questioning the government's piracy prosecution and are asking a judge to dismiss the charges.

The attorneys claim in court documents that the prosecutors' definition of piracy would make pirates out of environmental activists attempting to blockade a whaling ship. The lawyers say the men did not seize or rob the ship, so their alleged actions fall short of the legal definition of piracy.

The six men face mandatory life terms if convicted in the April 10 attack on the USS Ashland off the coast of Africa.

The government said Tuesday it will respond in court.