Gen. David H. Petraeus on Wednesday marked an early and unwelcome milestone in his tenure as commander of Western forces here: apologizing after his troops accidentally killed five Afghan soldiers.
"Friendly fire" incidents are relatively rare, but they stir animosity among many in the Afghan military, whose partnership with the NATO force is central to President Obama's hopes that American troops can begin drawing down a year from now.
Afghan and NATO officials both said the incident was under investigation, but in the past, such accidental deaths have been blamed on poor communication and coordination and -- often -- nighttime confusion.
The five Afghan soldiers were killed before dawn by a NATO airstrike as they prepared to attack insurgents in the Andar district of Ghazni province, in south-central Afghanistan. Western spotters apparently mistook the Afghan troops for armed militants.
Petraeus, who formally assumed command of NATO's International Security Assistance Force on Sunday, conveyed personal regrets to the Afghan government, said ISAF spokesman Brig. Gen. Josef Blotz.
Afghan officials, though, made clear that such occurrences carry a political cost.
"We strongly condemn this incident," said Afghan Defense Ministry spokesman Gen. Zahir Azimi. "Unfortunately, this is not the first time it happened. … We hope at least this would be the last."
Azimi said the 4 a.m. airstrike occurred without warning.
Western military officials also had losses of their own to report: the deaths of three American soldiers a day earlier in a single explosion in the south. Insurgents have been using massive IEDs, or improvised explosive devices, which can penetrate many of the armored vehicles in use by NATO forces. As a result, it is not unusual for Western troops to die in clusters of three or more.
Newly arriving American troops are mainly being deployed in the south, the scene of a major Western military campaign that is unfolding, somewhat behind schedule, in and around the city of Kandahar. The troops are part of a 30,000-strong buildup Obama ordered late last year, which will bring the U.S. force to 100,000 by summer's end.
The south is the most lethal battlefield for Americans and the other national contingents serving there, primarily Canadian and British troops. Military officials said Wednesday that Britain would soon turn over one of the most dangerous districts of Helmand province, which adjoins Kandahar, to American forces.
The district, Sangin, has accounted for nearly one-third of all British war deaths in Afghanistan: 99 of 312, according to British press reports. American forces are to take control of the district in early winter.