Taliban fighters killed 15 Afghan guards working for a US security company who were guarding a convoy of fuel tankers in western Afghanistan, an official said Tuesday. Between six and eight vehicles with USPI - US Protection and Investigations - were guarding a convoy of fuel tankers when the Taliban fighters attacked early Tuesday, said Farah Gov. Muhaidin Baluch. Fifteen USPI guards were killed and five were wounded, Baluch said. One fuel tanker was set on fire, and the militants stole one of USPI's vehicles, he said. An employee with USPI said he didn't immediately have any information to release.