KABUL, Afghanistan - A roadside bomb probably intended for Afghan or NATO forces killed five civilians in southern Afghanistan, while militants killed six Afghans driving a convoy of trucks to a NATO base, officials said Sunday.

The bomb hit a taxi late Saturday in the Panjwayi district of Kandahar province, the site of heavy battles between NATO troops and Taliban fighters over the last 18 months.

Five civilians were killed and three wounded, said Shah Baran, the local government leader.

"Usually the Taliban are planting mines for Afghan and NATO forces, but this time it exploded on civilians," Baran said.

In neighboring Helmand province, militants attacked a convoy of trucks carrying gravel to a NATO base, killing four drivers and two security guards, said Koka, an Afghan who goes by one name and owns the security company that employed the guards.

And in Zabul province, the director of the province's Peace and Reconciliation Commission — which helps former fighters renounce militancy and re-enter lawful society — was killed by gunmen on the highway.

A security guard and driver were missing, said Gulab Shah Alikhail, the spokesman for Zabul's governor.

The Afghanistan NGO Safety Office, a security company that surveys the security situation in Afghanistan for aid workers and other groups, said in a year-end report that 1,977 civilians were killed in insurgency related violence last year.

The report said that insurgent attacks — including suicide and roadside bombs, gunfire, hangings and mortar fire — killed 933 Afghan civilians last year. The report said that international military forces killed 525 Afghan civilians in aerial bombings and ground maneuvers.

An Associated Press count based on official figures found that more than 6,500 people — mostly militants — died in insurgency related violence in 2007, the deadliest year in Afghanistan since the 2001 ouster of the Taliban.