Iraqi police say a suicide bomber blew himself up at a gathering of Iraqi soldiers and civilians celebrating Army Day in central Baghdad Sunday, killing at least 11 people and wounding 17 others.

An Iraqi official said the dead include police officers, soldiers and civilians.

Witnesses say the blast occurred as soldiers were singing and chanting in the Karrada neighborhood. A U.S. military spokesman said two Iraqi soldiers flung themselves onto the bomber just before the blast, absorbing some of the impact.

Army Day is an official holiday that marks the anniversary of the establishment of Iraq's army in 1921 with military parades and other ceremonies.

In separate violence Sunday, Iraqi police say a series of bombs exploded outside Christian churches and a convent in Mosul, in Nineveh province, wounding four people.

Also in the Iraqi capital Sunday, police say at least three people were killed and 11 wounded when a vehicle exploded outside a restaurant in the northern district of Qahira.

And, the U.S. military in Baghdad reported Monday that three suspected al-Qaida in Iraq terrorists were killed in airstrikes near Maderiyah Friday night and Saturday morning.

In a statement, the military said the individuals were burying weapons in the ground when soldiers spotted them.

Separately, the U.S. military reported that a roadside blast in Diyala province on Sunday killed one coalition soldier.

Some information for this report was provided by AP and Reuters.