Afghan and international forces have initiated an attempt to rescue 23 South Korean hostages their pro-Taleban captors have threatened to kill within hours.

Military officials said Sunday the rescue mission was under way south of Kabul. It began shortly after a South Korean delegation arrived in Afghanistan to start negotiations aimed at winning the release of the Christian evangelical hostages, who were abducted Thursday.

The Taleban set a seven p.m. Sunday deadline (1430 UTC) for an answer to its ultimatum that all South Korean troops leave Afghanistan. South Korea has said it will bring its 200 troops home by the end of the year, as had already been scheduled.

Negotiations over the fate of the South Korean hostages will occur as authorities try to confirm the fate of two Germans taken hostage by Taleban militants last week.

The Taleban claims to have killed both Germans, but Afghan and German authorities say they believe one hostage died of a heart attack and the other is still alive.

German Foreign Minister Frank-Walter Steinmeier says the German hostage whose heart gave out apparently was a victim of stress. Steinmeier says Germany is doing everything possible to save the second captive's life. The two men were kidnapped Thursday in central Afghanistan. The Taleban says the foreigners' five Afghan colleagues were killed.

German Chancellor Angela Merkel has rejected the Taleban demands, and pledged that Germany's three thousand troops in Afghanistan will remain there.

Some information for this report provided by AP, AFP and Reuters.