Two Afghan policemen have been killed by coalition troops in the latest incident highlighting how difficult it can be to tell friend from enemy in Afghanistan. According to a U.S. military news release issued Sunday, the two policemen were killed by a combined Afghan-coalition patrol in Kapisa province late Friday night. The forces were part of an operation to "disrupt Taliban senior leadership and suicide attack networks in Kapisa," around 40 miles northeast of Kabul, the release read.

American officials said the coalition forces were "conducting a ground movement to their targeted location" when they spotted "several" individuals apparently maneuvering around them.

"Knowing a police checkpoint was nearby, the combined force suspected the individuals may be Afghan policemen and used various methods to identify itself as a friendly force," the release read. "Despite these efforts, which included having an interpreter and Afghan SOF [Special Operations Forces] engage the individuals in Pashtu, the ANP regrettably were undeterred and fired on the patrol. In self-defense, the patrol returned fire, killing two individuals."

The incident is under review, officials said.

"We sincerely regret the loss of life of our friendly forces and we are continually working with our Afghan partners to prevent situations like this from happening in the future," said U.S. Forces Afghanistan spokesman Col. Greg Julian. "I am truly saddened by this loss and wish to express my regrets to the families of the policemen killed in this incident."

Meanwhile, in southern Afghanistan, officials said the U.S. Marines and Afghan National Police have just completed an operation in Farah province.

Dubbed Operation Pathfinder, the effort included the 3rd Battalion, 8th Marine Regiment and National Police targeting insurgent cells in eastern Farah.

At least 11 suspected insurgents were detained in the operation and the forces found more than 150 pounds of military-grade explosives, bomb-making materials and several hand grenades and assault rifles.

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