4 U.S. Marines die in helicopter crash

? Four U.S. Marines died when a Sea Knight helicopter plunged into a lake in volatile Anbar province, the military said Monday, raising to 13 the number of American troops killed during a bloody weekend in Iraq.

It was the second military aircraft to go down in a week in Anbar, a stronghold of Sunni insurgents, although the military said mechanical problems rather than gunfire had forced the emergency landing Sunday.

“The pilots maintained control of the aircraft the entire time,” the military said.

A Marine was pulled from the water, but attempts to resuscitate him were unsuccessful. The bodies of three missing Marines were found in a subsequent search, the military said. Twelve other passengers survived.

Lt. Col. Christopher Garver, a U.S. military spokesman, declined to provide details about the twin-rotor CH-46 helicopter’s mission or the reason for its forced landing, saying the incident was under investigation.

The helicopter, from the 3rd Marine Aircraft wing, had the ability to land and taxi in the water in case of emergency. It came down in Lake Qadisiyah, a huge reservoir behind the hydroelectric dam at Haditha on the Euphrates River.

The deaths came on a weekend in which nine other U.S. troops were killed, including five in Anbar. The weekend’s violence pushed the total number of American service members who have died since the war started in March 2003 to at least 2,901.

A U.S. fighter jet also crashed last week in a field, killing the Air Force pilot.

Iraqi state TV, meanwhile, reported that Iraqi police found half a ton of explosives, including suicide belts and roadside bombs, in Anbar – a province the size of North Carolina that stretches west from Baghdad to the borders of Syria, Jordan and Saudi Arabia.

High numbers of U.S. casualties as well as a recent spike in violence between Shiites and Sunnis have contributed to doubts about the war in the U.S. These concerns were considered a major factor in the U.S. Democratic congressional victory.