A homicide bomber killed a district chief and three of his children in southern Afghanistan on Friday, while five civilians were killed in fighting between NATO soldiers and Taliban in the east, officials said.

The bomber blew himself up as Khariudin Achakzai, the chief of Kandahar's Zhari district, was coming out of his house with five of his children, said Abdul Ghafar, a police official.

Achakzai, two of his sons and a daughter were killed instantly, while two other sons were wounded, Ghafar said.

In the east, NATO troops were hit by a roadside bomb before coming under small-arms and mortar fire, the statement said. The alliance did not disclose the exact location of the incident.

The ensuing gunfight left five Afghan civilians dead and three others wounded, NATO said. Two Taliban fighters were also wounded.

There were no reports of alliance casualties.

"Such incidents are regrettable, and our thoughts and prayers are with the families and friends of those killed and wounded in this very unfortunate incident," the NATO statement said. "Every effort is being made to provide the best medical treatment to the injured Afghans."

Violence in Afghanistan has risen sharply during the last two months. More than 3,700 people, mostly militants, have been killed in insurgency-related violence this year, according to an Associated Press tally of casualty figures provided by Western and Afghan officials.