Updated

An Afghan policeman turned his gun on his colleagues at a police checkpoint in the country's south, killing seven policemen, a provincial official said Wednesday.

The incident late Tuesday night in the Uruzgan provincial capital of Tirin Kot was the latest among so-called insider attacks in which Afghan forces or gunmen in Afghan police or army uniforms turn their weapon on Afghan colleagues or NATO allies.

Earlier Tuesday, a gunman dressed as an Afghan soldier turned on allied troops at a military university on a base west of Kabul, killing an American major general and wounding about 15 U.S. and coalition forces, including a German general and two Afghan generals.

The slain American, 34-year-old Maj. Gen. Harold J. Greene, was the highest-ranked American officer killed in combat in the wars in both Afghanistan and Iraq. About half of the wounded were Americans, several of them reported to be in serious condition.

In the Uruzgan attack, provincial spokesman Doost Mohammad Nayab, said the attacker opened fire and shot and killed seven of his colleagues at the checkpoint, then stole their weapons and fled in a police car.

No one immediately claimed responsibility for the assault but Nayab says the shooter had Taliban connections and blamed the insurgents for the attack.

Insider attacks in Afghanistan rose sharply in 2012, with more than 60 coalition troops -- mostly Americans -- killed in 40-plus attacks that threatened to shatter all trust between Afghan and allied forces. U.S. commanders imposed a series of precautionary tactics, and the number of such attacks declined sharply last year.

On Tuesday, Taliban spokesman Zabihullah Mujahid praised in a statement the "Afghan soldier" who killed Greene. He did not claim his group carried out the attack, although in the past the Taliban have encouraged such actions.

Such assaults are sometimes claimed by the Taliban insurgency as proof of their infiltration. Others are attributed to personal disputes or resentment by Afghans who have soured on the continued international presence in their country more than a dozen years after the fall of the Taliban from power.