The U.S. Navy said the guided-missile frigate that struck an underwater mine in the Persian Gulf was out of danger Friday. Two of the 10 seamen injured were in critical condition.

The USS Samuel B. Roberts was being towed to Dubai, Navy officials said."The ship is under control. It is out of danger," said U.S. Central Command spokesman Lt. Col. John Head. The Navy declined to give the exact location of the ship.

Iran said it fired six missiles on Iraqi economic and military installations in the cities of Basra, Ali-gharbi and Khaneghein. There was no immediate confirmation from Iraq.

Iran's official Islamic Republic News Agency earlier reported that 13 civilians were killed and a number of others injured in overnight Iraqi bombing raids on the western Iranian cities of Hamadan and Bakhtaran.

Pentagon officials said today that the Roberts encountered a mine field with numerous mines before its hull was ripped open by one of the underwater explosives.

The frigate had come to an almost complete stop in the water at the time of the explosion after successfully maneuvering away from several mines spotted by lookouts, the officials said.

The effort to maneuver out of the mine field was hampered by rough seas, however, and the mine the Roberts eventually hit was probably moored to the bottom, the officials said.

The Navy said the 3,700-ton Roberts was in no danger of sinking. The explosion occurred about 55 miles northeast of the Qatar peninsula while the Roberts was on patrol.

Four of the injured seamen were taken to Bahrain's Salmaniya hospital. Head said two were suffering from second-degree burns over 40 percent of their bodies and were in critical condition.

The third had second-degree burns over 15 percent of his body, while the fourth was suffering from lower-back problems and smoke inhalation.

The other six injured sailors were under observation aboard the combat store ship San Jose. Head said they were listed in good condition.