South Korean President Roh Moo-hyun speaks to the nation during a news conference for kidnapped South Koreans in Afghanistan at the Presidental Blue House in Seoul July 21, 2007. Taliban insurgents have kidnapped 23 Korean Christians from a bus in Afghanistan, officials said on Friday, the biggest group of foreigners seized so far in the militant campaign to oust the government and its Western backers. [Reuters]

KABUL, Afghanistan - Taliban militants threatened Friday to kill a group of abducted South Korean Christians, including 15 women, within 24 hours unless the Asian nation withdraws its 200 troops from Afghanistan. South Korea said Saturday it plans to withdraw its forces by the end of this year as scheduled.

Foreign Minister Song Min-soon told reporters in Seoul that 23 South Koreans were kidnapped and indicated they are safe. A purported Taliban spokesman said Friday that the group was holding 18 Koreans.

In the largest abduction of foreigners since the fall of the Taliban regime in 2001, several dozen fighters kidnapped the South Koreans at gunpoint from a bus in Ghazni province on Thursday, said Ali Shah Ahmadzai, the provincial police chief.

"They have got until tomorrow (Saturday) at noon to withdraw their troops from Afghanistan, or otherwise we will kill the 18 Koreans," Qari Yousuf Ahmadi, who claims to speak for the Taliban, told The Associated Press on a satellite telephone from an undisclosed location. "Right now, they are safe and sound."

South Korea has about 200 troops serving with an 8,000-strong U.S.-led force, which is separate from the 40,000-member NATO-led force.

"The government is in preparations to implement its plan" to pull its troops out of Afghanistan by the end of this year as previously planned," Song said. South Korea's government has not received any official demand from the militants, he added.

South Korea plans to send officials to Afghanistan later Saturday for consultations with their Afghan counterparts to try to secure the release of the South Koreans.

Afghanistan has also set up a special task force and pledged that it will do everything to win the South Koreans' freedom, Song said of his telephone conversation with his Afghan counterpart.

It was unclear what the kidnapped Koreans were doing in Afghanistan.

A year ago, hundreds of South Korean Christians were ordered to leave Afghanistan amid rumors they were proselytizing in the deeply conservative Islamic nation. A member of that group promised they would return to the country in smaller groups, but denied charges of spreading Christianity.

South Korea's Yonhap news agency reported that most of the hostages were members of the Saemmul Community Church in Bundang, just south of the South Korean capital, Seoul.

An official at the Presbyterian church confirmed 20 of its members were in Afghanistan for volunteer work. The group left South Korea on July 13 and was to return on July 23, she said, speaking on condition of anonymity because she was not authorized to talk to the media.

Outmatched by foreign troops, the Taliban often resort to kidnapping civilians caught traveling on treacherous roads, particularly in the country's south, where the insurgency is raging. The tactic hurts President Hamid Karzai's government by discouraging foreigners involved in reconstruction projects from venturing into remote areas where their help is most needed.

The Koreans were seized as they traveled on a privately rented bus along the main highway from Kabul to the southern city of Kandahar, Ahmadzai said. The militants drove the bus into the desert before abandoning the vehicle and forcing the group to walk for about one hour, he said.

He said the group was in the northern city of Mazar-e-Sharif before it arrived in Kabul.

There were conflicting reports on how many Koreans were kidnapped.

The South Koreans' bus driver, released late Thursday, said there were 18 women and five men on the bus, Ahmadzai said. The Taliban spokesman said 15 women and three men were seized.

The abductions came a day after two Germans and five of Afghan colleagues working on a dam project were kidnapped in central Wardak province.

Ahmadi said the Taliban were also holding the two Germans, and threatened to kill them if Germany did not withdraw its 3,000 troops from a NATO-led force by noon Saturday ¡ª the same deadline as he gave South Korea.

Germany's Foreign Ministry said it was "aware of the statement by the so-called spokesman of the Taliban" but that it contradicted a statement the previous day that the Taliban was not holding the Germans.

"We will continue to carefully monitor developments of the situation," ministry spokesman Martin Jaeger said. "All necessary steps have been taken. The crisis team continues to work toward a swift release of the two kidnapped men."

On June 28, another German man was kidnapped in western Afghanistan, but was released after a week.