South Korea and relatives of 21 kidnapped Koreans appealed for U.S. help Tuesday, but Afghanistan 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 group was seized nearly two weeks ago; the group's pastor was killed last week.
Purported Taliban spokesman Qari Yousef Ahmadi said more Koreans will die unless eight prisoners are released today. He said some of the prisoners are being held at the U.S. base in Bagram.
The militants have extended several deadlines without consequences, but they killed Shim Sung Min, 29, on Monday after a deadline passed. His body, with a gunshot wound to the head, was found in Andar district.
The South Koreans - 16 women and seven men - were kidnapped 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."
State Department spokesman Tom Casey said there is regular contact between U.S. and South Korean officials on the standoff, but he 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 for the move.
A civilian grand jury in El Paso, Texas, is investigating the deaths of two Afghan detainees at a U.S. jail in Bagram, Afghanistan, nearly five years ago, according to current and former service members who said they have testified. The rare federal court inquiry follows the convictions in courts-martial of six soldiers on charges of abusing detainees, including the two men who died. It's unclear who the targets of the new investigation are or what may have prompted it now.