Eleven Afghan police killed in 'insider attack'

The incident occurred while the policemen were sleeping in their barracks in the provincial capital Lashkar Gah, as the Taliban escalate a deadly winter campaign of violence.

Bloodied corpses of the policemen were strewn around the checkpoint, many of them shot from close range, witnesses said, in a setback for Afghan forces before what is expected to be another fierce spring fighting season. "A policeman affiliated to the Taliban shot 11 of his colleagues, killing all of them," a provincial official said, declining to be named.

"He then fled the area, taking all the ammunition and firearms with him," he said, adding that police had launched a search for the Taliban infiltrator. The Boost government hospital in Lashkar Gah had received the bodies of the 11 policemen, a health official said.

Taliban insurgents, who control vast swathes of the opium-ravaged province, claimed responsibility for the killings. So-called insider attacks — when Afghan soldiers and police turn their guns on their colleagues or on international troops — have been a major problem during the more than 15-year-long war. Such attacks have sapped morale and caused deep mistrust within security ranks.

In a similar incident last September, two Afghan soldiers with suspected Taliban links killed at least 12 of their comrades as they slept in the volatile northern province of Kunduz.

Afghan security forces are battling a resurgent Taliban amid record casualties and mass desertions. For years, Helmand was the centrepiece of the Western military intervention in Afghanistan, only for it to slip deeper into a quagmire of instability. 

The Taliban effectively control or contest 10 of the 14 districts in Helmand, the deadliest province for British and US troops over the past decade and blighted by a huge opium harvest that helps fund the insurgency.

Lashkar Gah -- one of the last government-held enclaves in Helmand -- also risks falling to the Taliban's repeated ferocious assaults.

The intensified fighting in the province last year forced thousands to flee to the city from outlying districts.

Repeated bids to launch peace negotiations with the Taliban have failed and an intense new fighting season is expected to kick off in the spring.

The Pentagon this year said it will deploy some 300 US Marines this spring to Helmand.

NATO officially ended its combat mission in December 2014, but US forces were granted greater powers last June to strike at the insurgents as Washington vowed a more aggressive campaign.