A purported Taliban spokesman said Sunday that the hard-line militia was extending by 24 hours the deadline for the Afghan government to trade captured militants for 23 South Korean hostages.

Qari Yousef Ahmadi, who claims to speak for the Taliban, said the militants were giving the Afghan and South Korean governments until 7 p.m. (1430 GMT) Monday to respond to their demand that 23 Taliban prisoners be freed in exchange for the Koreans. Ahmadi previously said the deadline was 7 p.m. (1430 GMT) Sunday.

A police chief in Ghazni province said Afghan officials and elders had met with the kidnappers Sunday to resolve the crisis. U.S. and Afghan troops also surrounded the area in southern Ghazni province where the Koreans are thought to be held in case military commanders decide to carry out a rescue operation.

"As soon as we receive the order, we will start the operation," said Defense Ministry spokesman Gen. Mohammad Zahir Azimi.

Neither the Afghan nor Korean governments have commented on the purported Taliban offer. A delegation of eight Korean officials arrived in Kabul on Sunday and met with President Hamid Karzai over the crisis.

Ahmadi said Taliban commanders wanted to give the South Korean government an extra 24 hours to persuade the Afghan government to release the Taliban prisoners, and a U.S. spokesman said a rescue operation appeared unlikely for the moment.

"We will only launch rescue operations or military action at the request of the Afghan and Korean governments," said Lt. Col. David Accetta. "We do not want to jeopardize the lives of the Korean civilians."

Earlier on Sunday, villagers found the body of a German aid worker kidnapped in neighboring Wardak province on Wednesday along with another German and five Afghans, said provincial police chief Mohammad Hewas Mazlum.

Ahamdi, the purported Taliban spokesman, said Saturday that militants shot and killed the Germans because their country hadn't pledged to pull its 3,000 troops from Afghanistan. But Afghan and German officials said intelligence reports indicated that one died of a heart attack and the other was still alive.

Mazlum said he did not immediately know the cause of death of the German whose body was recovered.

The militants kidnapped the Koreans on Thursday while they were riding on a bus from Kabul to the southern city of Kandahar, where they live and work, some at medical facilities.

Khwaja Mohammad Sidiqi, the police chief of Ghazni province's Qarabagh district, where the Koreans were kidnapped, said the delegation of Afghan officials and elders traveled to speak with the kidnappers but hadn't yet returned with any news late Sunday.

A senior South Korean official said officials would negotiate with the Taliban through intermediaries. The official spoke on condition of anonymity because of the sensitivity of the issue.

The 23 Koreans, including 18 women, work at an aid organization in Kandahar, said Sidney Serena, a political affairs officer at the South Korean Embassy.

Though the Koreans have been reported to be Christians, Serena said the embassy "strongly denies" that they were carrying out any sort of religious activities.

Relatives back in South Korea pressed their government to win the captives' safe release, while hundreds of supporters staged a candlelight vigil.

"Sister, I promise that I'll be good and take care of you. So please come back safely," Lee Jung-hoon, younger brother of hostage Lee Jung-ran, told reporters as he held back tears.

"I would not really have any other wish ... if the Taliban send our family members home safely," said Seo Jung-bae, father of two of the hostages, who gathered with relatives at a church in Bundang just south of Seoul to watch television for updates on the situation.

Some 300 peace activists along with students and several lawmakers held a candlelight vigil in downtown Seoul to renew their call on the government to immediately withdraw its troops from Afghanistan. The troop withdrawal had been the initial demand of the kidnappers' purported spokesman.

South Korea's military presence in Afghanistan "is not for peace, but it fuels war," said Kwon Young-ghil, a lawmaker for the progressive Democratic Labor Party.

South Korea has about 200 troops serving with the 8,000-strong U.S.-led coalition in Afghanistan, largely working on humanitarian projects such as medical assistance and reconstruction.

The South Korean government informed the National Assembly late last year that it would terminate its military mission in Afghanistan before the end of this year.

Earlier Sunday, the Defense Ministry said it has begun preparations to pull its troops out of Afghanistan by the end of this year as previously scheduled, stressing the process had begun well before the purported Taliban demand for their withdrawal.

Another person at the vigil, 22-year-old student Kim Yea-seul, called on the Taliban to release her fellow South Koreans, saying the whole world is watching the militant group.

"The kidnapping and killing of innocent civilians can never be tolerated under any circumstances," she said.