Four American soldiers were killed during combat in Baghdad, including three in a single roadside bombing, the U.S. military said Friday.

Three soldiers were killed and 11 wounded Thursday when a bomb exploded near their combat patrol in eastern Baghdad, the military said in a statement. Four of the wounded were treated and returned to duty, it said.

Another soldier was killed and three wounded the same day during combat operations in a western section of the capital, an earlier statement said. The military did not release details of the incident.

All the victims were assigned to Multi-National Division-Baghdad. Their names were withheld pending family notification.

On Thursday, the military had announced three soldier deaths: two killed in a mortar or rocket attack Tuesday, and another killed in a roadside bombing Wednesday.

At least 3,663 members of the U.S. military have died since the beginning of the Iraq war in March 2003, according to an Associated Press count. The figure includes seven military civilians.