A U.S. helicopter carrying 16 Marines went down in a lake west of the Iraqi capital in volatile Anbar province, killing four of them, the military said Monday.
The twin-rotor CH-46 helicopter from 3rd Marine Aircraft Wing made the emergency landing Sunday near the shore of Lake Qadisiyah "in which the pilots maintained control of the aircraft the entire time."
It said the helicopter had experienced mechanical problems and was not hit by gunfire.
Twelve passengers survived the crash; a Marine was pulled from the water but attempts to resuscitate him were unsuccessful. A search was then conducted for three missing Marines whose bodies were found, the military said.
The crash occurred in Anbar province, where many of Iraq's Sunni Arab insurgent groups are based and where many U.S. Marines die in battles with the militants.
The death of the Marines raised to 13 the number of American service members who died this weekend in Iraq, an unusually high casualty toll for American forces over a two-day period.
The death brought to at least 2,897 the number of members of the U.S. military who have died since the Iraq war started in March 2003, according to an Associated Press count.
On Saturday and Sunday, eight, and two soldiers were wounded, in Baghdad or north of the capital.
More Iraqis fell victim Monday as well. At least six were killed in a drive-by shooting and a car bombing.
In the worst attack, suspected militants killed three government agricultural engineers and their driver in a drive-by shooting as they headed to work Monday morning in Baqouba, 35 miles northeast of Baghdad.
A similar attack about 13 miles to the north killed a man and woman driving in the town of Khalis. The deaths were reported by police who spoke on condition of anonymity to protect their safety in Diyala, a province where heavy fighting has taken place recently with insurgents who often target Iraqi security forces.
In Mosul, 225 miles northwest of Baghdad, a suicide car bomber attacked a U.S. military convoy and wounded five nearby Iraqi civilians, said Dr. Bahaldin al-Barki, who works at the hospital where they were taken. No U.S. casualties were reported.
In northern Baghdad, American forces killed two insurgents and detained six during a raid on buildings where insurgents with ties to al Qaeda in Iraq were making car bombs, the U.S. command said. A weapons cache including artillery rounds and AK-47s also was found.
In other developments: