U.S. troop kills Afghan guard at base in northern Afghanistan KABUL - Panicked by a wave of deadly attacks against foreign troops involving rouge Afghan forces, an American soldier fatally shot an Afghan guard Friday night at a U.S. base in northern Afghanistan, according to a provincial governor. The guard was on duty at the gate of a base in Sar-i-Pul when the incident occurred. Provincial governor Sayed Anwar Rahmati said the U.S. soldier opened a door and saw the barrel of the guard's gun. Feeling threatened, he shot. "It was a mistaken act and happened due to the threat the soldier had felt from the guard," Rahmati said by phone. A spokesman for the NATO-led troops in Kabul said the coalition was aware of the report, but he refused to provide further details, saying an investigation was underway. According to reports, a dozen foreign troops have been killed recently, some of them by Afghan forces at joint bases. In the worst incident in recent months, four unarmed French troops were killed by an Afghan soldier northeast of Kabul. The incident followed a similar attack against French troops by a man wearing an Afghan army uniform a few weeks prior. After the deaths, French officials announced the country plans to withdraw its combat troops from Afghanistan by 2013, earlier than scheduled. Some of the attacks have been blamed on personal, cultural and religious disputes, while others have been in retaliation for civilian casualties during foreign operations. Taliban-led insurgents have also taken credit for some of the attacks, infiltrating the ranks of Afghan forces as they take on a greater security role in preparation for the withdrawal of international troops. The attacks have caused distrust among international forces serving on joint duty or providing training for Afghan forces.