KABUL - An Afghan border policeman killed six American servicemen during a training mission Monday, underscoring one of the risks in a U.S.-led program to educate enough recruits to turn over the lead for security to Afghan forces by 2014.
The shooting in a remote area near the Pakistani border appeared to be the deadliest attack of its kind in at least two years.
Attacks on NATO troops by Afghan policemen or soldiers, although still rare, have increased as the coalition has accelerated the program. Other problems with the rapidly growing security forces include drug use, widespread illiteracy and high rates of attrition.
A spokesman for the Afghan Interior Ministry, Zemeri Bashary, confirmed that the gunman in yesterday's attack was a border police officer rather than an insurgent who donned the uniform for a day.
The Taliban claimed responsibility, saying the gunman joined the border police to kill foreign soldiers.
The shooter opened fire on the NATO troops and then was killed in the shootout, NATO said, without providing additional details.
Col. Dave Lapan, a Pentagon spokesman, confirmed that the six killed were American. He declined to provide their identities or say which military branch they were from until next of kin could be notified.
Bashary said the incident happened in the Pachir Wagam district of Nangarhar province, a volatile area near Pakistan.
After two deadly shootings in July, NATO officers said they were re-examining training practices to make sure that such attacks did not happen again.
In the past year, the size of the Afghan police force grew 27 percent from about 95,000 officers to 120,500. The army increased 42 percent from 97,000 soldiers to about 138,200.
There have been also been problems with retention, and even those who stay often are lacking the most basic skills.
Drug use is also common among the police, though NATO trainers say they are doing a better job of screening for drugs and kicking out addicts.