BAGHDAD, Iraq — Three American soldiers were killed yesterday in the Sunni insurgent area west of Baghdad, and Iraqi officials said about 1,500 people died violently last month in the capital — many shot execution-style by sectarian death squads.

The soldiers were assigned to the 1st Brigade, 1st Armored Division, an American statement said. The brigade operates around Ramadi, which is the capital of Anbar province, where support for the Sunni insurgency is strong.

In addition, two Americans were missing yesterday after a UH-60 Black Hawk helicopter went down the day before in Anbar province. The helicopter crashed in an unspecified body of water, and divers were searching for the missing troops, the military said. The crash was not due to hostile fire, the American government said.

The deaths brought to at least 17 the number of American service members killed in Iraq this month. All but five died in Anbar, indicating the ongoing threat from Sunni insurgents at a time when attention has focused on violence between Sunnis and Shiites in Baghdad.

Yesterday, the deputy health minister, Dr. Sabah al-Husseini, said about 1,500 violent deaths were reported last month in the Baghdad area, excluding members of the American-led coalition.

Four people were killed and five wounded when fighting erupted late yesterday between gunmen and residents of a Shiite community in north Baghdad, a police lieutenant, Salim Ali, said.

Four people were killed and 16 wounded in an explosion late Tuesday at a Shiite mosque in Baqouba, a religiously mixed city 35 miles northeast of Baghdad.