KABUL, Afghanistan - Taliban fighters killed 15 Afghan guards and wounded five who were working for a private security company who were protecting a convoy of fuel tankers in western Afghanistan, an official said yesterday. Six Taliban were killed in the ensuing fight.

Six to eight vehicles of the security company were guarding the fuel tankers when the Taliban attacked early yesterday, said Farah province's governor, Muhaidin Baluch. In addition to the killed and wounded guards, a tanker was set afire, he said.

Baluch said the guards worked for USPI - Houston-based US Protection & Investigations, but two USPI employees contacted by the Associated Press said their company was not involved.

They spoke on condition of anonymity because they were not authorized to talk to reporters. One of the employees said Afghan officials in the south tend to identify all security companies as USPI, even when they are not.

Gen. Khail Buz Sherzai, the provincial police chief, said he was not sure of the security company's name.

Baluch said the tankers were traveling from the western city of Herat to a military outpost in Lashkar Gah, the capital of Helmand province in the country's south that has seen the heaviest fighting this year.

On Monday, a U.S.-led coalition air strike on a Taliban commander as well as a subsequent operation in Helmand killed several militants, the coalition said. The strike targeted a Taliban commander involved in the movement of foreign fighters and suicide bombers, it said.

More than 6,300 people, mostly militants, have been killed in the insurgency in Afghanistan this year, according to an AP count based on official figures.

The country has also seen a record number of suicide bomb attacks - more than 140 - in 2007.