At least 20 people were wounded when a man threw grenades at a police vehicle in eastern Afghanistan on Sunday, an official said.
Grenade attacks are relatively uncommon in Afghanistan but it was the second time in less than 48 hours that police have been targeted in such a way.
The attacker threw at least two grenades at a police pick-up truck in a crowded market in
Khost city before fleeing the area, Khost provincial police spokesman Mir Akbar Mangal told AFP.
"Twenty people, including several police, were wounded in the attack. No one has been killed," he said. Police are hunting the attacker.
Khost province borders the
Pakistan tribal areas and is a stronghold of the Haqqani militant group, which has links to al-Qaeda and the Taliban.
There was no immediate claim of responsibility, but the Taliban has said it was behind a grenade attack on a police station in Kabul on Friday night.
Police said nobody was injured after a man lobbed at least one grenade at a district police station in the west of the capital.
The insurgents, who have been fighting NATO-led foreign troops and Afghan government forces for a decade, use roadside and suicide bombs more than grenades.
The United Nations said the number of civilians killed in violence in Afghanistan rose by 15 per cent in the first six months of this year to 1,462, with insurgents blamed for 80 per cent of the killings.
There are about 140,000 international troops, mainly from the United States, in Afghanistan helping government forces combat the insurgency.