KABUL, Afghanistan -- An Afghan policeman opened fire on NATO forces and Afghan soldiers Monday in the fifth attack reported in a week by Afghan security forces on their international partners. The U.S.-led military coalition says none of its service members were killed.
A Taliban spokesman claimed responsibility for the shooting in the eastern province of Nangarhar, saying the attacker was a police officer who had been in contact with insurgents before the assault.
A recent rash of "green-on-blue" attacks, in which Afghan security forces or attackers wearing their uniforms turn their guns on the coalition troops training them, has raised worries about a deterioration of trust between the two sides, just over two years before NATO is set to turn over security to local forces and pull out most of its troops.
Taliban insurgents are eager to exploit such a rift.
The trend also raises renewed concern that insurgents may be infiltrating the Afghan army and police, despite intensified screening.
NATO spokesman Charlie Stadtlander said an initial investigation indicated the attacker was an Afghan police officer, though the man was wearing civilian clothes.
He said there were no NATO deaths but would not say if any international service members were wounded in the attack, citing coalition policy.
At least one Afghan intelligence agent was wounded in Monday's shooting, according to according to Ahmad Zia Abdulzai, spokesman for the Nangarhar provincial governor.
"The shooter has escaped, and Afghan security forces are looking for him," Abdulzai said.
Taliban spokesman Zabiullah Mujahid issued a statement Monday afternoon praising the shooting. He said the police attacker had been "waiting for such an opportunity to attack" international forces.
Mujahid said three Americans were killed, though the insurgents often exaggerate the results of their attacks and are quick to adopt any incident that allows them to claim support among Afghans.
Coalition officials say a few rogue policemen and soldiers should not taint the overall integrity of the Afghan security forces, and that the attacks have not impeded plans to hand over security to Afghan forces -- which are supposed to reach a strength of 352,000 in a few months -- by the end of 2014.
Green-on-blue attacks are on the rise. So far this year, 34 coalition troops have been killed in 27 attacks, compared to 11 attacks and 20 deaths in 2011, according to an Associated Press count, and five attacks in each of the previous two years.
At least seven American service members have been killed in the past week by either their Afghan counterparts or attackers wearing their uniforms.
Of those, six died in two separate attacks on Friday in different areas of the volatile southern province of Helmand.
NATO has said both attackers have been detained, though it has released little information about the shootings, and accounts from other officials differ.