The Taliban said they had abducted 12 security guards, and two of their own fighters had been killed.

One fuel tanker was reportedly set on fire and a USPI vehicle was taken. Colonel Saydo Khan, a police official, said reinforcements had been sent to the area and were fighting the attackers in a nearby village.

Thousands of people work for Texas-based USPI in Afghanistan.

More than 6,300 people, mostly Taliban or al-Qaeda fighters, have been killed in violence in Afghanistan this year, according to an Associated Press news agency count based on official figures.