KUNDUZ: An Afghan official says Taliban gunmen have killed seven policemen in an ambush in the northern Kunduz province.

Nasruddin Khan, Governor of Dashti Archi district, said the policemen were travelling to a neighbouring province to collect their salaries when they were ambushed by up to 30 militants.

In the Parwan province north of Kabul, four policemen were killed while manning a security post on Wednesday night in Syagurd district, said Governor Mohammad Sayed Sediqi.

Afghanistan's Taliban insurgency is spread thinly across the country but continues to prey on police manning checkpoints, which are easy targets.

In 2014, more than 5,000 policemen were killed by insurgents, raising concerns about the force's sustainability.

Also read: 26 Afghan police killed as army begins anti-Taliban drive

At least 20 Afghan policemen were killed last month in a Taliban attack near Kabul, bringing to 26 the number of officers to die since the start of an army offensive aimed at weakening the insurgents.

The attack came as police and troops, in their first major assault since US-led Nato forces ended their combat mission last December, began targeting militants on Monday in restive Helmand province, a hotbed of the Taliban insurgency and a hub for drug trafficking.

Violence across Afghanistan hit record levels in 2014, with civilian and military casualties the worst since the 2001 invasion. According to United Nations data, more than 3,000 civilians were killed in 2014, up 18 per cent on 2013.