The abductees are believed to include at least 18 South Korean Christian volunteers taken from a bus on the Kabul-to-Kandahar highway and two Germans who were on their way to oversee a construction project west of Kabul.
Various reports have put the number of South Korean hostages at upward of 18, all of them Christian volunteers and all but a few of them women.
"We believe that about 20 South Korean travelers in Afghanistan were kidnapped [south] of Kabul on the afternoon of July 19," South Korean Foreign Ministry spokesman Cho Hee-yong said, outlining what officials know about the incident at a news briefing today in Seoul.
The leaders of their church back in South Korea say they are in Afghanistan as part of a Christian mission, heightening fears that they might be mistreated by radical Islamist militants.
Afghan Interior Ministry spokesman Zemari Bashari was quoted today as saying that the Koreans were "very carelessly traveling in a chartered bus" when armed men stopped the vehicle and led them away.
A South Korean Embassy source suggested that negotiations were under way with the kidnappers, saying they were also demanding the release of Taliban prisoners in Afghan jails.
Cho said South Korean officials are doing what they can to secure their release. "Our government will make every effort to return those kidnapped Koreans as quickly as possible and safely," he said.
Threats To Missionaries
South Korea has no combat troops in Afghanistan but reportedly fields around 200 medical staff and engineers there.
Afghan authorities last year turned back around 2,000 South Korean Christians, citing concerns for their safety amid local suggestions that they were there to proselytize. Hundreds of Koreans came anyway but were subsequently expelled.
Afghanistan is an Islamic republic where conversion from Islam or attempting to convert Muslims can be regarded as serious crimes.
Meanwhile, a Taliban spokesman has threatened the execution of the two Germans unless all 3,000 German troops in Afghanistan are withdrawn and all Taliban prisoners in the country released.
Spokesman Qari Yusof Ahmadi says Taliban fighters kidnapped the two Germans and five Afghans in Wardak Province on July 18.
In Berlin today, the German Foreign Ministry downplayed reports that the Taliban is behind the abductions. Spokesman Martin Jaeger said there are "contradictions" between different claims about the abductions.
But the ministry also stressed that an "emergency task force is working very intensively on a quick release of both men."
(with material from Reuters, dpa)