BAGHDAD, Iraq (CNN) -- Three Iraqi soldiers may have helped avoid further casualties when they subdued a suicide bomber Sunday at a celebration in central Baghdad, the U.S. military said.
All three soldiers, along with four police officers and four civilians, were killed and 17 people were wounded in the explosion at the Army Day rally, an Interior Ministry official said.
The bombing was one of several separate attacks in Iraq on Sunday that together claimed at least 16 lives. Also Sunday, gunmen shot to death a Shiite tribal sheikh, Iraqi officials said.
The Army Day rally attack occurred about 12:30 p.m. as people participated in an event called "The Gathering for Iraq" in the Karrada district of central Baghdad, the official said. Watch the destruction from a day of attacks »
Prior to the attack, a non-governmental organization was bestowing gifts on the soldiers and civilians.
"These martyrs gave their lives so that others might live," U.S. military spokesman Lt. Col. Steve Stover said about the three soldiers.
In a second attack, a bomb in a parked car in northeastern Baghdad exploded Sunday afternoon and killed four people, including a police officer, the Interior Ministry official said.
Eleven others were wounded in the attack, which occurred near an Iraqi police patrol on a crowded street in the Qahira neighborhood.
In the Nahda commercial area in central Baghdad, one civilian was killed and four others wounded when another car bomb exploded about 2:30 p.m.
An Interior Ministry official said 15 cars were damaged in four mortar rounds that followed the explosion.
In Mosul, two car bombs and three improvised bombs exploded at four churches in the northern Iraq city, wounding four civilians and damaging the buildings, a Mosul police official told CNN.
Mosul is a predominantly Sunni city located in Nineveh province, about 260 miles north of the capital.
The Shiite tribal sheikh who was killed Sunday was part of an effort to form an armed group to combat militias in his neighborhood, the Interior Ministry official said.
Sheikh Ismaiel Abbas was killed instantly when gunmen in two cars attacked him near his home in the Shaab Shiite neighborhood at 8 a.m., an Interior Ministry official said.
Witnesses told investigators the gunmen were Shiite militia members, but police are still investigating, the official said. E-mail to a friend
CNN's Mohammed Tawfeeq contributed to this report.
All About Iraq War