Deb Riechmann

KABUL, Afghanistan: Afghan security forces shot and killed three international troops Monday, one of them an American, in two attacks. They were the latest in a rising number of attacks in which Afghan forces have turned their weapons on their foreign partners.

The killings reflect a spike in tensions between Afghan and international forces that follow an American soldier’s alleged massacre of Afghan civilians, the burning of Muslim holy books at a U.S. base, and uncertainty about Afghanistan’s fate as foreign troops prepare to pull out.

They also come at a time when international troops have stepped up training and mentoring of Afghan soldiers, police and government workers so that Afghans can take the lead and the foreign forces can go home. The success of that partnership is key to the U.S.-led coalition’s strategy to withdraw most foreign combat forces by the end of 2014.

U.S. Marine Gen. John Allen, the top commander of U.S. and NATO forces in Afghanistan, told reporters at the Pentagon that these types of attacks are characteristic of any warfare involving insurgents.

“We experienced these in Iraq. We experienced them in Vietnam,” Allen said. “On any occasion where you’re dealing with an insurgency and where you’re also growing an indigenous force … the enemy’s going to do all that they can to disrupt both the counterinsurgency operations” and the developing nation’s security forces.

Since 2007, an estimated 80 NATO service members were killed by Afghan security forces, according to an Associated Press tally, which is based on Pentagon figures released in February. More than 75 percent of the attacks have occurred in the past two years.

Sixteen NATO service members — 18 percent of the 84 foreign troops killed so far this year — have been shot and killed by Afghan soldiers and policemen or militants disguised in their uniforms, according to the AP tally.

In one incident Monday, two British service members were killed by an Afghan soldier in front of the main gate of a joint civilian-military base in southern Afghanistan, the coalition said. Another NATO service member was shot and killed at a checkpoint in eastern Afghanistan by a man who was believed to be a member of a village-level fighting force the U.S. is fostering in hopes of countering the Taliban insurgency. The Pentagon confirmed Monday that the dead soldier was American but did not release further details.

Maj. Ian Lawrence, a British military spokesman for Task Force Helmand, said one of the British troops was a Royal Marine and the other was a soldier from the British Adjutant General’s Corps. They were killed in front of the base in Lashkar Gah, the provincial capital of Helmand province.

While they acknowledge that these type of attacks are on the rise, coalition officials say they must be viewed in context. They say there are about 100,000 coalition troops working side-by-side with more than 300,000 Afghan troops.

“In most cases, the relationship is very strong. They know each other well,” Allen said.