BAGHDAD, Iraq —Insurgents shot down a U.S. helicopter south of Baghdad and killed two soldiers, bringing the weekend death toll of American service members to seven, the U.S. military said today.

The helicopter attack occurred Sunday during fighting in Youssifiyah, 12 miles south of the Iraqi capital, the military said.

It was the second helicopter shot down in the past six weeks over that area, commonly known as the "Triangle of Death" because of the large number of insurgent attacks. An Apache helicopter went down there April 1.

Two U.S. Marines died Sunday during unspecified "enemy action" in Anbar Province, the area of western Iraq that is the heart of the Sunni-Arab led insurgency, the U.S. command said. Two U.S. Army soldiers also died Sunday in a roadside bomb attack in Baghdad, and another U.S. soldier was killed by a roadside bomb in Baghdad on Saturday.

The fatalities raised to 2,443 the number of U.S. military personnel who have died since the war began in 2003, according to a count by The Associated Press.

The U.S. command also said American soldiers and helicopters conducted four raids over the weekend in the Triangle of Death, killing 16 suspected al-Qaida insurgents, including one militant who allegedly had led the April 1 attack, during which two U.S. soldiers were killed when their AH-64 Apache helicopter was shot down in the Youssifiyah area.

After that attack, a new al-Qaida group claimed responsibility and posted a gruesome video on the Web showing men dragging the burning body of what appeared to be an American soldier across a field as they shouted "Allahu akbar!" or "God is great!"

It was not known if the weekend raids were related to Sunday's helicopter crash as well.

Four Iraqi civilians and two suspected militants were wounded during the raids Saturday and Sunday around Latifiyah, 20 miles south of Baghdad, the military said. The wounded civilians included two women, one of whom was pregnant, and two children, the U.S. command said. All were treated or were evacuated to a U.S. military hospital.

In other attacks today, militants fired more than 30 mortar rounds at a British military camp in southern Iraq, wounding four soldiers.

Elsewhere, eight Iraqis were killed, including one in a roadside bomb attack that hit an oil tanker, sending a large plume of black smoke billowing over central Baghdad.