Members of the Iraqi security forces in the neighborhood said American troops might have set a pattern making them vulnerable by regularly visiting the Awakening Council building once or twice each week.

Image An Iraqi man grieved over the body of his brother on Thursday in Kirkuk after a suicide bomb attack killed eight people. Credit... Marwan Ibrahim/Agence France-Presse — Getty Images

The United States military confirmed three deaths, while the Iraqi Army said four American soldiers had died. The explosion also killed at least 12 civilians and wounded 25 others, said a police official who spoke on the condition of anonymity because he was not authorized to speak to the news media.

Two weeks ago, a bomb placed in the bed of a pickup truck under sacks of potatoes exploded at a produce market in the same neighborhood, killing 10 people and wounding 37. Before this month, the Dora district had been mostly free of violence over the past year after many of the neighborhood’s insurgents joined Awakening Councils.

About one hour before the Dora attack, a bomb placed inside a trash container at a Baghdad police station killed at least 2 police officers and wounded 20 other people, police officials said.

Among the wounded at the police station in Al Mamoon district in central Baghdad was the station’s commander, said a police officer at the scene who spoke on the condition of anonymity because he was not authorized to speak to the news media.

An American soldier and at least 12 Iraqi police officers were also hurt, according to the Iraqi police. Witnesses said American troops often visited the police station between 9 and 10 a.m., when the attackers struck. The United States military did not immediately confirm the wounding of the soldier.