The families of a group of South Korean Christians held hostage by the Taleban pleaded desperately today for American help in securing their freedom as they mourned the death of a second captive.

Afghan officials this morning found the bullet-ridden body of Shim Sung Min, a 29-year-old IT worker, dumped in a field of clover in a village near the eastern city of Ghazni.

Shim was one of a group of 23 South Koreans kidnapped by the Taleban two weeks ago and the second one to be killed. His abductors threatened to kill other hostages unless the Afghan Government agrees by noon (0730GMT) tomorrow to meet their demands for the release of Taleban prisoners.

Shim's death shook South Korea, where his mother cried hysterically after hearing last night that the victim may have been her son."Why did you kill him? Please save his life," she said through her tears.

A Foreign Ministry spokesman, Cho Hee Yong, confirmed the hostage's identity and gave an angry warning that further deaths in the hostage stand-off would not go unanswered.

"The Government expresses deep condolences to his family. We cannot contain our anger at this merciless killing and strongly condemn this," Mr Cho said. "The Government makes it clear that it will not tolerate any further acts of harming innocent Koreans and holds the perpetrators responsible."

The captors have demanded the release of Taleban prisoners in exchange for the Koreans' lives. But President Hamid Karzai was strongly criticised earlier this year for agreeing to release a group of Taleban prisoners in exchange for an Italian journalist, and his spokesman, Humayn Hamidzada, said today that bowing to the extremists' demands would encourage more abductions.

"We shouldn’t encourage kidnapping by actually accepting their demands," he said. "If we keep on responding positively to the demands of terrorists, we will face more problems."

In South Korea, the families appealed for American help in securing the release of the group, which includes 18 women.

"We appeal for support from the people of the United States and around the world for resolving this crisis as early as possible," said Kim Jung Ja, mother of Lee Sun Young.

"Especially, the families want the United States to disregard political interests and give more active support to save the 21 innocent lives," she said, reading a statement before other grieving relatives at the Saemmul Community Church in Bundang, just outside Seoul. "This is not an issue about religion, ideology or nationality. This is a matter where the precious lives of family members are on the line."

The Taleban killed the second hostage only hours after the Afghan Government said that it had negotiated a stay of execution for the captives.

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