GHAZNI, Afghanistan - Two top Taliban leaders and four South Korean officials met face-to-face for the first time Friday to negotiate the fate of 21 members of a church group held hostage for three weeks, an Afghan official said.

Taliban spokesman Qari Yousef Ahmadi said two members of the top militant council -- Mullah Bashir and Mullah Nasorullah -- travelled to the central Afghan city of Ghazni, near where the South Koreans were kidnapped on July 19. He said the government in Kabul gave the Taliban a written guarantee that the two officials would be safe.

The meeting began Friday evening at the office of the Afghan Red Cross in Ghazni, said the Afghan official, who asked not to be identified because he was not authorized to release the information. He said four members of the International Committee of the Red Cross were also participating.

The Afghan and local governments did not immediately comment. The Interior Ministry spokesman said he was not aware of a meeting taking place.

Ahmadi also said the Taliban would not kill any of the 21 remaining South Korean hostages until the face-to-face meetings have been held. Two men among the 23 South Koreans originally kidnapped have already been killed.

The captors have repeatedly threatened to kill more hostages if their demands to release Taliban prisoners held by the Afghan government and the U.S. military are not met.

The Afghan government has said it will not release prisoners because doing so could encourage more kidnappings. Afghan authorities say talks with the Taliban are the best way to resolve the problem.

The local governor, Marajudin Pathan, has said a ransom payment might resolve the crisis.

The South Korean government has issued guidelines to its aid organizations telling them to leave Afghanistan by the end of the month for safety reasons, a South Korean Embassy official said on condition of anonymity due to policy.

Last month, the government banned its citizens from travelling to Afghanistan.

Ahmadi said the departure of Korean aid workers would have a "positive effect.'' He did not elaborate.

In South Korea, a spokesman for the hostages' families said Friday that the mothers of several hostages _ five women and a translator _ will travel to the emirate of Dubai next week to seek help from the Arab world in securing their loved ones' release.

"The reason why we are sending women, especially mothers, to Dubai is that Islamic culture has more sympathy for women,'' said the spokesman, Cha Sung-min.

The 23 South Koreans were abducted in the Qarabagh district of Ghazni province as they travelled by bus from Kabul to the southern city of Kandahar. The captives -- volunteers from a church group who planned to do health work in Afghanistan -- include 16 women and five men.