Protesters demanding US engage in negotiations for safe return of hostages in Afghanistan, and withdraw US troops from S. Korea, in Seoul, 14 Aug 2007

South Korea's foreign ministry is calling for the release of 19 Korean hostages still held by Taleban kidnappers in Afghanistan.

On Monday, the Taleban freed two of 21 South Korean Christian aid workers held hostage for nearly a month.

Kidnappers called the release a goodwill gesture. The two women were handed over to Red Cross officials, who then turned them over to South Korean authorities in southern Afghanistan.

Families expressed relief that the women are free and appear to be in good condition but they said they are worried about those still being held.

Monday's release followed several days of talks between the Taleban and South Korean officials, mediated by the Red Cross.

Two male hostages were executed late last month after the Afghan government failed to meet Taleban demands to release militant prisoners.

The 23 South Koreans traveled to Afghanistan despite a travel ban by the South Korean government. They were abducted July 19 while traveling through Ghazni province on a humanitarian mission.

Also Monday, the Taleban arranged for a man who identified himself as kidnapped German national Rudolf Blechschmidt to call news agencies.

In the calls, the man said he was very sick and that his captors wanted to kill him. He asked the German and Afghan governments to secure his release.

News agencies were not able to confirm the callers' identity. The Taleban abducted Blechschmidt last month along with another German man, who was shot by his kidnappers, and four Afghans.

Some information for this report was provided by AFP and AP.