Kabul - The fate of 22 South Korean Christian volunteers kidnapped by the Taliban in Afghanistan hung in the balance on Thursday, a day after the rebels shot dead one hostage and dumped his bullet-ridden body near where the group was seized.

The Taliban said the Afghan government had been given until late Wednesday night to agree to exchange the group for eight imprisoned rebels, but the deadline passed without word from the kidnappers or government.

Earlier reports by some media that eight hostages had been released have been denied by officials, negotiators and a spokesman for the Taliban.

"Yes, they have killed one of the hostages and efforts are under way to have the others released," said Khowja Seddiqi, district chief of Qarabagh in Ghazni province where the crisis has unfolded.

A relative of South Koreans kidnapped in Afghanistan reacts as they watching TV news reports on negotiations in Seoul, Wednesday, July 25, 2007. Taliban militants claimed they shot and killed one Korean hostage on Wednesday while a group of abductees was freed and taken to a US military base, officials said. [AP]

South Korea's government strongly condemned the murder of the yet unnamed male hostage, calling it an unforgiveable atrocity.

"The government and the people of South Korea condemn the kidnapping of innocent civilians and the atrocity of harming a human life," said Baek Jong-chun, presidential Blue House chief national security adviser.

"Harming innocent civilians can never be justified and we will never forgive this kind of inhumane act," he said in a nationally televised statement.

The Taliban accused the government and South Korean negotiators of failing to act in good faith after Kabul rejected the demand for eight named rebels to be freed from prison.

Initially the Taliban had also insisted South Korea withdraw all its troops serving with an international force in Afghanistan -- something Seoul had planned to do before the end of the year anyway.

NOT LISTENING

"Since Kabul's administration did not listen to our demand and did not free our prisoners, the Taliban shot dead a male Korean hostage," Qari Mohammad Yousuf told Reuters by telephone from an unknown location.

Yousuf said one hostage had been killed in a desert area close to where the 23 Koreans -- 18 women and five men -- were abducted on the main road south from Kabul last week.

Afghan President Hamid Karzai has pledged not to swap prisoners for hostages after being criticized at home and abroad for releasing five Taliban from jail in March in exchange for an Italian reporter.

The president and ministers have remained silent throughout the latest hostage ordeal, but Seoul said it would soon dispatch a special envoy to step up coordination with Kabul.

The kidnappings have made travel outside major cities risky for the thousands of foreign aid workers and U.N. staff in Afghanistan and may weaken support for military involvement among the more than 30 nations with troops in the country.

The past 18 months has seen rising violence in Afghanistan, with daily clashes between Taliban insurgents and Afghan and foreign troops. Suicide and roadside bomb attacks have spread to areas previously considered safe.

Anxious family members of the Korean hostages have gathered at the offices of a non-governmental agency in Seoul to follow developments on television. Sounds of crying emerged on Wednesday when the news came out that one of the hostages had been killed.

About 1,000 people went to the church that sent the volunteers to Afghanistan to pray for their safe return, the broadcaster YTN reported.