KABUL, Afghanistan (AP) — A newly recruited Afghan village policeman opened fire on his American allies today, minutes after they gave him a new weapon as a present, killing two U.S. service members. It was the latest in a disturbing string of attacks by Afghan security forces on the international troops training them.

The killings in the country’s far west marked the sixth time in two weeks that a member of the Afghan security forces, or someone wearing their uniform, opened fire on international forces.

Such attacks — virtually unheard of just a few years ago — have recently escalated, killing at least 36 foreign troops so far this year and raising questions about the strategy to train national police and soldiers to take over security and fight insurgents after most foreign troops leave the country by the end of 2014.

The NATO-led coalition has said such attacks are anomalies stemming from personal disputes, but the supreme leader of the Taliban boasted on Thursday night that the insurgents are infiltrating the quickly expanding Afghan forces.

Today’s attacker was identified as Mohammad Ismail, a man in his 30s who had joined the Afghan Local Police just five days ago.

He opened fire during an inauguration ceremony attended by American and Afghan national forces in the Kinisk village in the far western province of Farah, provincial police chief Agha Noor Kemtoz said.

“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,” Kemtoz said.

Ismail was shot and killed as the coalition and Afghan forces returned fire, the police chief said.

A spokesman for the international coalition force, Jamie Graybeal, confirmed that two American service members were killed today by a member of the Afghan Local Police, a village defense force that is being trained by international forces, including U.S. special forces.

Graybeal said the attack happened in Farah but gave no other details other than confirming the shooter had been killed.

The attack came at about 8 a.m. today after the U.S. forces arrived in the village of Kinisk to train members of the local police, Kemtoz said. He said one Afghan National Police officer was also seriously wounded in the shooting.

So far in 2012, there have been 28 attacks reported on foreign troops by Afghans they are training, compared to 11 attacks in 2011, according to an Associated Press count, and five attacks in each of the previous two years.

Six such attacks have come in the past two weeks alone, with six American troops killed last Friday in two separate shootings in Helmand province in the south and another American killed a few days previously on a U.S. base in Paktia province in the east.