Taliban insurgents ambushed an Afghan police convoy today, killing five people.
Along with four policemen, a senior former provincial official was killed in the clash in the southern province of Helmand, provincial spokesman Mahaiuddin said.
"I do not have more details about it or of possible Taliban losses," he added.
Violence has flared in southern Afghanistan, the Taliban heartland, as NATO troops move in to take over from the US military to allow Washington to pull out 3,000 soldiers.
The latest attack in the bloodiest phase of violence since US-led forces toppled the Islamist government in 2002.
Taliban spokesman Qari Mohammad Yousuf said guerrillas from the fundamentalist movement were behind the ambush.
Almost 1,000 people have been killed in Taliban violence and coalition-led operations in Afghanistan this year, including more than 40 foreign soldiers, most of them Americans.
The US military last week announced its biggest operation since ousting the Taliban in 2001 to crush the militants in the south. Operation Mountain Thrust has involved several air strikes.
Already it has carried out 340 air strikes over the past three months, more than double the 160 conducted in Iraq, the Washington Postreported today.
Citing figures from the US military headquarters in the Middle East, the newspaper said strikes had increased in recent days as the military launched counter-offensives against militants in the south and southeast.
The report quoted US military officials as saying the activity was in response to increasing aggression by the Taliban.
Almost 40 foreign soldiers have been killed in combat in Afghanistan this year, nearly 30 of them Americans, in the worst upsurge of violence since 2001.
Meanwhile, four schoolchildren died and 15 were injured in a stampede today after a fire broke out in the kitchen of their building in the western city of Herat.
Provincial police chief Mohammad Ayoub Salangi said: "The fire started to engulf a nearby classroom and the children started to flee. Four girl children were killed and 15 others were hurt in the stampede."
The fire was brought under control, he said.