The killing of two South Korean hostages by the Taleban left the Afghan Government and coalition forces with few options. For the past two weeks, intermediaries have been negotiating against the clock to persuade those who captured 23 Christian aid workers to release them. Their captors, however, have insisted on the release of Taleban prisoners, a demand that the Government of President Karzai, after the humiliating release of inmates in March in exchange for the life of an Italian journalist, has said it will not meet. When the threatened killings began, after the expiry of several Taleban deadlines, it became clear that the insurgents were not to be talked out of their murderous blackmail.

Public opinion in South Korea is outraged. Seoul has come under enormous pressure to do something – anything – to save the captives, and has in turn beseeched the Americans to intervene. But any rescue mission is fraught with risk. The Taleban have repeatedly said that the use of force would jeopardise the lives of the Koreans. Where they are held and how they are being treated is unclear, but Afghan and coalition special forces must assume that the Taleban have already placed explosives near the captives so that they can be quickly killed during a rescue attempt. Yesterday Kabul announced that an unspecified military operation had begun in the southern province of Ghazni, and urged civilians to leave the area. Bloodshed appears inevitable.

Bargaining over the lives of hostages is always excruciating. Terrorists play on the mismatch between the value that Western societies place on human life and the callous brutality of those who recruit and use suicide bombers. The Taleban have a record of ruthlessness that is only emboldened by appeasement. Their military campaign is faltering, as overdue reinforcements reach the troops of the International Security Assistance Force and better strategies deny them sanctuary in the villages. Their response has been to copy the terrorist tactics used in Iraq, targeting allied convoys with suicide attacks and seizing foreigners or government officials.

Two weeks ago, in the same province, the Taleban kidnapped four Afghan judges, whose bodies were found yesterday. A day before abducting the Koreans, they also seized two German aid workers and five Afghan colleagues. One German has been found shot dead and one Afghan escaped. The others are still being held to enforce a demand for the withdrawal of all 3,000 German troops from Afghanistan. Commendably, Angela Merkel, the German Chancellor, has said that Berlin will not give in to the kidnappers’ demands.

By now, the world should have some idea of the tactics and brutality of the Taleban. It is astonishing, and deeply regrettable, that outsiders as naive as the Koreans should have considered going to Afghanistan, or that their Government allowed them to do so. Only fellow Muslims are likely to have any sway over these extremists. This, perhaps, is the reason why, so far, none of the Korean women has been killed. Killing innocent men is equally abhorrent, but even the Taleban appear reluctant to turn on women. If so, the Muslim world still has some slight chance of averting tragedy. It should speak out, unambiguously, on the evil of killing hostages, male or female. Not in the name of Islam should Christian missionaries be slaughtered by terrorists.