BAGHDAD, Iraq – Insurgents shot down an American helicopter during a raid against Al Qaeda terrorists south of Baghdad and killed two soldiers, bringing the weekend death toll of American service members to seven, the American military said yesterday.

The military also said American forces killed more than 40 militants, including an Al Qaeda operative, in five raids south of Baghdad in an area commonly known as the “Triangle of Death” because of the large number of insurgent attacks.

America hopes a national unity government that includes Shiites, Sunnis, and Kurds will sap the insurgency’s strength, but Iraqi politicians struggled against a deadline to form such a government. And with at least 20 Iraqis killed in roadside bombings and driveby shootings yesterday, sectarian violence showed no signs of letting up.

The helicopter was downed after an American operation in Youssifiyah, about 12 miles south of Baghdad. The Mujahedeen Shura Council, a coalition of insurgent groups that includes Al Qaeda in Iraq, claimed responsibility in a statement posted on the Internet.

Other Americans killed over the weekend included two American Marines who died Sunday during unspecified “enemy action” in Anbar province, the area of western Iraq that is the heart of the Sunni-led insurgency. Two soldiers died Sunday in a roadside bomb attack in Baghdad, and another died in a roadside bomb in the capital Saturday.

The deaths raised to at least 2,443 the number of American military personnel who have died since the war began in 2003, according to a count by the Associated Press.

The five American raids south of Baghdad resulted in the killing of an Al Qaeda terrorist blamed for an April 1 attack in the same area that downed an American Apache helicopter and killed two soldiers.