A South Korean special envoy, Baek Jong-chun, is expected to hold talks with Afghan President Hamid Karzai in Kabul Saturday to step up efforts to free 22 South Koreans held hostage by the Taleban.
Another negotiating deadline set by the insurgents passed Friday with no word on the hostages' fate.
A purported Taleban spokesman said earlier the hostages were still alive, although the Associated Press quoted the spokesman as saying some of the captives were in bad health.
Negotiators say they are struggling with conflicting demands made by the kidnappers, including the release of several Taleban prisoners, withdrawal of South Korean troops from the country and money from South Korea.
The kidnappers shot and killed the 42-year-old leader of the South Korean Christian aid group earlier this week.
On Thursday, a woman identified as female hostage Lim Hyun-joo made a phone call to reporters, pleading for help in resolving the situation.
The hostages traveled to Afghanistan despite a ban by the South Korean government. There has been criticism of them in South Korea for putting themselves in a dangerous situation.
South Korean President Roh Moo-hyun canceled his upcoming summer vacation to concentrate on the crisis.
Some information for this report was provided by AP and AFP