The government called for the immediate release of 21 South Koreans kidnapped in Afghanistan as a deadline loomed today.

"As Muslims, the hostage takers must not resort to such action to pursue their agenda," a statement from the Malaysian foreign affairs ministry late Tuesday said.

"The holding and killing of hostages will not solve problems. We appeal to them to show compassion to the innocent Koreans. For the sake of humanity, Malaysia hopes the hostage takers will release them immediately."

The hardline Islamic Taliban militia has already shot dead two of the South Korean aid workers.

They want at least eight Taliban prisoners freed from Afghan jails and said that if their demands were not met by 0730 GMT Wednesday, they would start killing the rest of the hostages.

Negotiations were apparently at a standstill.

Malaysia is chair of the 57-member Organisation of the Islamic Conference. On Monday the group issued a statement from its Jeddah headquarters calling for the South Koreans' immediate release.

There were also new fears Wednesday for a German engineer held in Afghanistan since July 18, a day before the 23 South Koreans were captured.

Al-Jazeera television broadcast late Tuesday a video that it said showed him pleading for his life.