Taliban militants ambushed a police patrol in western Afghanistan, killing eight policemen and losing at least four of their own fighters, police said on Sunday.
The fighting in the province of Farah erupted late Saturday after dozens of Taliban rebels ambushed a police patrol, Farah police chief Sayed Agha Saqeb said.
"Eight police were killed and two wounded," Saqeb said. About 17 rebels were believed killed and wounded during six hours of fighting, but only four bodies were recovered from the battlefield, he said.
"The fighting ceased when we sent reinforcements," Saqeb said.
Ministry of interior spokesman Zemarai Bashary confirmed the attack.
Western Afghanistan has previously been comparatively free of violence, with the Taliban-led insurgency most intense in the south and southeast of the country.
The latest battle was in Farah's Bala Baluk district which has seen a surge in Taliban activity this year.
Police in early April raided a religious school in the district and arrested 22 people, alleging the madrassa was involved in organising Taliban suicide attacks.
The school was being used as a "terrorist centre" and was supported by Pakistani nationals and Arabs, police said.
In late February the nearby town of Bakwa was overrun by Taliban fighters who were in control for less than 24 hours before Afghan security forces drove them out.
Authorities detained the Bakwa district governor and his police commander for alleged links with the Taliban.
A Taliban suicide bombing on a convoy delivering the new police chief to his post on March 12 killed the officer and nine of his men.
The neighbouring province of Herat, on the border with Iran, has also seen an increase in unrest. US Special Forces and other foreign and Afghan troops say they killed 136 Taliban fighters in battles there last weekend.
Separate Afghan and UN reports say around 50 civilians, including women and children, were also killed.