GHAZNI, Afghanistan - Police discovered the body of a second South Korean hostage slain by the Taliban in central Afghanistan while the group threatened Tuesday to kill more hostages if their demands were not met by Wednesday, the latest of several deadlines.

The body of Shim Sung-min, 29, one of the South Korean hostages is carried to load in the back of a vehicle by policemen after he was killed by the Taliban militants in Ghazni province, west of Kabul, Afghanistan on Tuesday, July 31, 2007. Police in central Afghanistan at daybreak Tuesday discovered the body of a second South Korean hostage slain by the Taliban, officials said. [AP]

South Korea, meanwhile, pleaded with the international community to set aside the normal practice of refusing to cave into hostage-takers' demands, as it urged a peaceful resolution to a standoff. Twenty-one South Koreans remain captive.

"The (South Korean) government is well aware of how the international community deals with these kinds of abduction cases," said a statement from the president's office. "But it also believes that it would be worthwhile to use flexibility in the cause of saving the precious lives of those still in captivity and is appealing (to) the international community to do so."

The comments came after Afghan officials found the body of Shim Sung-min, 29, a former information technology worker who was volunteering with the South Korean church group on an aid mission to Afghanistan.

He was killed Monday after two deadlines given by the Taliban demanding the release of insurgent prisoners passed with no action. Last week the church group's leader, Pastor Bae Hyung-kyu, was fatally shot in unclear circumstances.

A purported Taliban spokesman, Qari Yousef Ahmadi, said senior Taliban leaders decided to kill Shim because the government had not met Taliban demands to trade prisoners for the Christian volunteers, who were in their 13th day of captivity Tuesday.

"The Kabul and Korean governments are lying and cheating. They did not meet their promise of releasing Taliban prisoners," Ahmadi, who claims to speak for the Taliban, said by phone from an undisclosed location.

The Taliban commanders set a new deadline of noon on Wednesday.

"If the Kabul government does not release the Taliban prisoners, then we will kill after 12 o'clock ¡ª we are going to kill the Korean hostages," Ahmadi said. "It might be a man or a woman ... It might be one. It might be two, four. It might be all of them."

The body was found on the side of the road at daybreak Tuesday in the village of Arizo Kalley in Andar District, about 5 miles west of Ghazni city, said Abdul Rahim Deciwal, the chief administrator in the area.

An Associated Press reporter at the scene said the man appeared to have a gunshot wound to the right temple.

Shim, who had recently left his job to prepare for graduate school, had previously visited the Philippines for five days as a volunteer worker and also had served as an army officer.

His father, Shim Jin-pyo, told reporters earlier Tuesday that he wondered how the Taliban "could perpetrate this horrible thing."

"I think they act like they are not human beings," he said.

The Al-Jazeera television network, meanwhile, showed shaky footage of what it said were several South Korean hostages. It did not say how it obtained the video. The authenticity of the video could not immediately be verified.

Some seven female hostages, heads veiled in accordance with the Islamic law enforced by the Taliban, were seen crouching in the dark, eyes closed or staring at the ground, expressionless.

The hostages did not speak as they were filmed by the hand-held camera.

The Taliban kidnapped the 23 South Koreans, who were riding on a bus through Ghazni province on the Kabul-Kandahar highway on July 19, the largest group of foreign hostages taken in Afghanistan since the 2001 U.S.-led invasion.

Seoul noted it did not have the power to comply with the Taliban demands "because it doesn't have any effective means to influence decisions of the Afghan government." It's not clear if the Afghan government would consider releasing any militant prisoners, a key Taliban demand.

In March, President Hamid Karzai approved a deal that saw five captive Taliban fighters freed for the release of Italian reporter Daniele Mastrogiacomo. Karzai, who was criticized by the United States and European capitals over the exchange, called the trade a one-time deal.

On Sunday, Karzai and other Afghan officials tried to shame the Taliban into releasing the female captives by appealing to a tradition of cultural hospitality and chivalry. They called the kidnapping of women "un-Islamic."