Afghan National police and U.S. Marines do a joint patrol through the town of Golestan in Afghanistan's Farah Province in 2009

Afghan National police and U.S. Marines do a joint patrol through the town of Golestan in Afghanistan's Farah Province in 2009 David Guttenfelder/AP

Two U.S. troops killed by Afghan policeman

This is the sixth such attack in just two weeks.

One week after deadly attacks that left six American soldiers dead at the hands of Afghan troops, two more U.S. service members were killed in a similar round of violence on Friday, the Associated Press reported.

Mohammad Ismail, a newly recruited Afghan village policeman signed up just five days earlier, opened fire on American soldiers tasked to train him, just minutes after being given a new weapon as a gift.

“As soon as they gave the weapon to Ismail to begin training, suddenly he took the gun and opened fire toward the U.S. soldiers,” Farah provincial police chief Agha Noor Kemtoz told AP.

Ismail was shot and killed by NATO and Afghan forces, who returned fire.

This is the sixth so-called "green-on-blue" attack in just two weeks. Last Friday, six American service members were killed in two separate attacks. The Pentagon has launched an investigation into the shootings to determine the motivation behind the attacks.

Hours later, another member of Afghan security forces opened fire on NATO troops in Kandahar, but there were no casualties, the AP reported.