KABUL (Reuters) - An Afghan policeman shot dead at least eight fellow officers, burned their bodies and took their weapons to join Taliban militants, provincial officials said on Thursday, adding to the toll from dozens of insider attacks in this year alone.

The latest insider attack occurred in northeastern Takhar province, and came just days after a U.S. soldier was killed by an Afghan policeman in eastern Logar province, the second American to be killed in an insider attack this year.

“The incident happened early Thursday morning, after a local police opened fire on his colleagues sleeping in a checkpoint in Khwaja Ghar district,” Takhar provincial police spokesman, Khalil Asir said. He said the bodies were later set on fire and burned.

The perpetrator was apparently connected with the Taliban, Asir said, adding that he fled to the group taking weapons.

Insider attacks by Afghan soldiers or police or by attackers wearing uniform have been a major problem in recent years. There are far more insider attacks on Afghan security forces than on Western forces.

Between December and May, there were 47 so-called “green-on-green” attacks involving members of the Afghan security forces turning on their colleagues, with casualties from insider attacks up 50 percent, according to a Pentagon report in June.

In a separate incident, 11 members of the security forces were killed after Taliban stormed several checkpoints in the western province of Badghis, late on Wednesday.

The attacks happened in Ab Kamari district, provincial spokesman, Jamshid Shahabi said, adding that in a clash lasting several hours, 24 Taliban insurgents were killed or wounded.