Leading article: Aid workers and armed force

The killing of the British doctor and aid worker, Karen Woo, and nine of her colleagues in the wilds of north-eastern Afghanistan, is a tragedy for all concerned: for the victims, for their families and friends, but also for the many Afghans who benefited from their work. The suggestion that they were killed because they were seen by their attackers as Christian missionaries is a particularly ominous claim that could be interpreted as a threat to other work associated with Christian charities. But such an assumption would be premature. A Christian aid worker, Gayle Williams, was killed in Kabul almost two years ago as she walked to work, but there is scant evidence of the systematic targeting of Western religious charities.

Much more needs to emerge about the precise circumstances of this attack before any reliable conclusions can be drawn. If, as has been speculated, it was a robbery, that would be one thing. It would make the case for even sterner warnings about safety, and it would add Badakhshan, hitherto regarded as one of the safer areas of a very unsafe country, to the list of danger zones. But it would have no wider implications.

But there are two other questions that need to be answered. One concerns the role, or not, of the Taliban. While local people have reportedly complained about increasing insurgent activity in recent months, this is not a region where the Taliban have generally been active. Indeed, it is one of the few provinces not to have been controlled by the Taliban before 2001. Yet a spokesman for the group claimed almost at once that the aid workers were killed because they carried Bibles. If the Taliban are now active here, their reach may now extend further than it is currently known to be. Then again, the claim may be wishful thinking or plain wrong.

The other question relates to aid work and how it may dovetail in places with Nato military operations. In this case, the group appears to have travelled independently, hiring its own guards who were let go once they entered the supposed safety of Badakhshan. Elsewhere, however, tensions have arisen between charities and the military, because of the risk aid workers see in being associated with those who use armed force.

This does not appear to have been a factor in these killings. But the dependence of aid workers on the military for security, and the reliance of the military on aid organisations for the civilian reconstruction projects that are vital to winning over the local population, make for a volatile mix that risks endangering all concerned.