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

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

Earlier on Tuesday, an Afghan soldier turned on allied troops at a military university on a base west of Kabul, the capital, killing US Major General Harold J Greene, and wounding about 15 US and coalition forces, including a German general and two Afghan generals.

Greene was the most senior US soldier to have been killed during the Afghan conflict.

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 said the shooter had Taliban connections and blamed the group for the attack.

Insider attacks in Afghanistan rose sharply in 2012, with more than 60 coalition troops, mostly from the US, killed in 40-plus incidents that threaten to shatter the trust between Afghan and coalition forces.

Taliban spokesman Zabihullah Mujahid has praised the Afghan soldier who killed Greene in a statement.

On Wednesday, US officials prepared to fly the body of the two-star general back home.

An Afghan military official said the soldier who killed Greene hid in a bathroom before his assault and used a NATO machine gun in his attack.

The official identified the soldier as a man in his early 20s, Rafiqullah, who came from Paktia province.

Speaking on the condition of anonymity, he told the AP news agency that no motive had been established for the shooting in which Rafiqullah also was killed.

(Aljazeera)