mortar attack (search) Sunday killed two U.S. soldiers and left 16 wounded — one critically — at a base west of the Iraqi capital.

Maj. Richard Spiegel of the Army's 13th Corps Support Command said the mortar barrage slammed into Logistical Base Seitz (search), on Baghdad's western outskirts, around 6 p.m. local time.

Eight of the injured were evacuated by air to the Army's 31st Combat Support Hospital in Baghdad, where the two later died of their wounds, Spiegel said.

One wounded soldier was listed in critical condition, and four others returned to duty. Names of the dead and wounded were being withheld pending next-of-kin notification.

The soldiers killed and wounded all belonged to the Army's 13th Corps Support Command (search), which oversees distribution of military fuel, food, water and other supplies to U.S. forces across Iraq.

As of Friday, 976 U.S. service members have died since the beginning of military operations in Iraq in March 2003, according to the Defense Department.

U.S. bases are daily targets of insurgents' mortar and rocket barrages. Most of the munitions explode without injury.

Also Sunday, a car bomb exploded outside an air base used by U.S. forces near Dijiel, about 25 miles north of Baghdad, injuring one American soldier and two Iraqi civilians, the U.S. military said. Three suspects were detained near the site of the attack, said Army Sgt. Robert Powell.