Afghan officials say a car bombing outside a Kandahar police headquarters killed five police officers and two civilians Sunday.

Officials say 19 others were wounded, including 10 civilians, in the bomb attack in southern Afghanistan.

So far, no one has claimed responsibility for the deadly blast.

The explosion comes a day after a top U.S. military commander in Afghanistan called on the Taliban to stop the killing of innocent men, women and children.

General John Allen was responding to a new United Nations report that said 3,021 civilians were killed in Afghanistan in 2011.

The U.N. report said 2011 was the fifth year in a row that civilian casualties increased, jumping 8 percent from 2010.

The reports said insurgents were responsible for more than 2,300 deaths, compared to just 410 civilian deaths by NATO or Afghan government forces.