Slaughter in Helmand as Taliban fighters deliver show of power

US Marines unable to prevent 17 victims having throats slit by insurgents

Taliban fighters cut the throats of 17 civilians in a remote corner of Helmand province this weekend in a grim reminder of how much power the insurgents still wield in large swaths of Afghanistan, despite Nato claims that they are on the run.

The massacre took place on Sunday afternoon in Kajaki, a district almost entirely in the insurgents' hands despite the efforts of thousands of hard-charging US Marines to claw the province back under government control.

As news of the attacks slowly filtered out yesterday, local officials claimed at first that the victims were party-goers whose failure to observe a strict segregation of the sexes had drawn the Taliban's wrath. But it seems just as likely – if not more so, given the area's profoundly conservative mores – that a Taliban crackdown on suspected government informants was to blame.

A third explanation proffered by Helmandi officials is that two Taliban commanders, called Mullah Sayed Gul and Mullah Wali Mohammad, quarrelled over the possession of two women, provoking a bloodbath. If true, it would not be the first time in Afghanistan that a clash between jealous lovers had sparked a gun battle, though it does not explain why the victims had their throats slit.

Whatever the truth, the competing versions of events illustrate the difficulties of pinning down hard facts in Afghanistan's more isolated districts, some of which, despite over a decade of intervention, still barely register on the map and are where unsubstantiated gossip can spread like wildfire. The UN mission in Afghanistan slammed the killings as a "criminal act" that "is unjustifiable and totally disregards the sanctity of human life".

Yet perhaps more worrying for the US-led coalition was news of yet another "green-on-blue" insider attack, in which an Afghan soldier opened fire on American troops he was patrolling with in the country's east, killing two before he was himself gunned down. The attack brought the number of coalition troops killed by the Afghan security forces to 42 this year, 12 of them this month alone, a grim indictment of Nato's exit strategy, which hinges on transferring security responsibilities to Afghan soldiers and police who, for the most part, are woefully ill-prepared for the task.

Yet again there is confusion over what really happened. One local official said the Afghan soldier had turned his weapon on his US allies after an argument erupted. But an Afghan Army spokesman claimed the Afghan soldier responsible for the killings had accidentally discharged his rifle as the patrol came under attack. "He didn't do this intentionally," Noman Hatefi said. "But then the commander of the [Afghan] unit started shouting at him, 'What did you do? You killed two Nato soldiers'! And so he threw down his weapon and started to run." At that point, Mr Hatefi said, an aircraft mistook the escaping soldier for an insurgent and opened fire, killing him.

Nato promptly issued a press release detailing the friendship that had built up between an Afghan army recruit stationed in Helmand and his US Marine mentor.

Meanwhile, unknown gunmen killed 10 Afghan soldiers at a checkpoint in Helmand's Washer district – a former Taliban redoubt ostensibly cleared by Afghan forces last year but, in reality, still very much in play.

Afghan officials are investigating whether five Afghan troops who appeared to have fled with their assailants abetted the attack.