"We will behead him," threatens a 25-year-old, self-proclaimed Taliban , as day-long negotiations on the fate of a shopkeeper abducted five days ago reach a critical point.

Four worried-looking male relatives of captured Abdul Ahmad sit with their backs against the wall in a house of a low-level Taliban commander in a part of Wardak province where the militants are in control, not the government.

There is no way these humble men, who have arrived from the town of Ghazni just a few dozen kilometres (miles) away, can meet the ransom demand of 12 PK machine guns and ammunition or the equivalent in cash -- roughly 1.4 million Pakistani rupees (17,000 dollars), the preferred currency here.

One resignedly repeats an Afghan expression: "If a whole city costs one rupee and you don''t have it, you can''t buy it."

Hafiz, the young Taliban who wears a scarf wrapped into a turban, gets angry.

"We will kill him," he fumes, adding that the shopkeeper''s head will be delivered the following day.

Again, the relatives explain that 35-year-old Ahmad is not with the government despite the documents found on him when he was pulled from a taxi travelling from Kabul to Ghazni .