GHAZNI, Afghanistan (AP) - Amid appeals by South Korea and relatives of 21 kidnapped Koreans to the United States for help, Afghanistan has said for the first time it will not release insurgent prisoners _ the Taliban's key demand to free the captives.
Afghan police found the body of the second hostage slain since the Christian church group was seized nearly two weeks ago; the group's pastor was killed last week.
A purported Taliban spokesman, meanwhile, said some of the prisoners the militants want released are held at the U.S. base at Bagram _ and the Al-Jazeera television network broadcast a video Tuesday reportedly of another Taliban captive, a German engineer.
The Taliban said more Koreans will die if its demands are not met by midday Wednesday. The militants have extended several previous deadlines without consequences, but killed 29-year-old Shim Sung-min on Monday after a deadline passed.
They were two of 23 South Koreans kidnapped while riding a bus July 19 on the Kabul-Kandahar highway. They are the largest group of foreign hostages taken in Afghanistan since the 2001 U.S.-led invasion that drove the Taliban from power.
In South Korea, relatives and a civic group pleaded for more U.S. involvement, and the president's office used more diplomatic language to prod the Americans.
"The government is well aware of how the international community deals with these kinds of abduction cases," the president's office said, an apparent reference to the U.S. policy of not negotiating with terrorists. "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."
State Department spokesman Tom Casey said there is regular contact between U.S. and South Korean officials on the standoff, but would not comment on specifics.
President Hamid Karzai's spokesman said officials were doing "everything we can" to secure the hostages' release, but that freeing militant prisoners was not an option.
"As a principle, we shouldn't encourage kidnapping by accepting their demands," said Humayun Hamidzada.
In March, Karzai authorized freeing five captive Taliban fighters for the release of an Italian reporter, but called the trade a one-time deal. He was roundly criticized by the United States and western nations for the move.
Qari Yousef Ahmadi, a purported Taliban spokesman, said eight prisoners must be released by midday Wednesday, and that some were held by the U.S. at Bagram.
In South Korea, the slain hostage's father, Shim Jin-pyo, described his son as "chivalrous and warmhearted," and wondered how the Taliban "could perpetrate this horrible thing."
Kim Jung-ja, the mother of another hostage, said the U.S. should "give more active support to save the 21 innocent lives."
In the minute-long video shown Tuesday on Al-Jazeera, a stocky man with graying hair stood in a rugged mountainous area surrounded by masked Taliban fighters.
The man seemed to be speaking to a camera but his voice was inaudible. Al-Jazeera said he appealed to the German government and the U.S. to withdraw troops from Afghanistan. The video also showed four Afghans whom it said were kidnapped with the German.
The broadcaster did not say how it obtained the video.
Two German engineers were reported kidnapped earlier this month by the Taliban. One of them died in captivity under unclear circumstances.
German media reported that the video included a demand for the release of 12 Taliban fighters in exchange for the German and four Afghans. But Al-Jazeera spokesman Ayman Gaballah told The Associated Press there was no specific mention of releasing 12 Taliban prisoners, only a call for compliance with Taliban demands.
In Germany, Foreign Ministry spokesman Martin Jaeger said the ministry was pressing efforts to secure the hostage's release.
Germany has 2,700 soldiers serving with the NATO-led force in Afghanistan.