A suicide explosion on Sunday killed at least 21 people in Baghdad, an interior ministry source said.

The assailant detonated an explosive vest at a gathering in the Abu Ghraib district, which is largely a Sunni area. The people were celebrating the release of prisoners from Camp Bucca, the source said on condition of anonymity.

The attack also left 32 people injured, the source said, adding children, women, police and local Sunni anti-terror neighborhood guards were among the victims.

The suicide bombing was the most serious in Baghdad after three female attackers killed more than 24 people and injured over 62 on July 28 during a Shiite pilgrimage gathering.

The U.S. military had said violence has dramatically dropped in Iraq, hitting a four-year low. Yet, sporadic suicide or car bombing attacks are still haunting the Iraqis and creating remarkable casualties.

(Xinhua News Agency August 25, 2008)