US forces have killed 22 suspected Taleban and al-Qaeda militants in a gun battle in southern Afghanistan, the US military says.
American troops and helicopters fought the insurgents in the Shinkay district of Zabul province, late on Sunday.
"Twenty-two anti-coalition militias were killed - three of them were Arabs," US military spokesman Major Scott Nelson said in Kabul.
Zabul province is widely regarded as a Taleban stronghold.
Major Nelson said three more suspected militants, including another Arab, had been captured in the latest fighting.
He said about 40 militants armed with AK-47s and rocket-propelled grenades had attacked American troops on patrol.
The US patrol called in Apache helicopter gunships
"Our soldiers were out doing a cordon search when they were engaged by a large force of anti-coalition militias," Major Nelson said.
The troops called in two Apache helicopter gunships which fired on the insurgents.
"Skirmishes continued throughout the night," Major Nelson said.
He said there were no US casualties.
The US troops seized a global positioning system and a video camera and tapes.
The US-led coalition has about 18,000 troops hunting Taleban and al-Qaeda militants in southern and eastern Afghanistan.
The insurgents have vowed to disrupt the Afghan presidential elections on 9 October.
Zabul is considered a huge security risk for aid workers and coalition forces.
In May, four US soldiers were killed there by suspected Taleban militants, one of the biggest losses for American forces since they began operations in Afghanistan more than two years ago.
Since the May attack, there have been a number of raids on Afghan government targets.