South Korean President Roh Moo-hyun on Saturday called for the release of 23 countrymen held hostage by Taliban fighters in Afghanistan, saying they were medical volunteers. The call came as the Taliban claimed on Saturday that it had killed one of the two German hostages it was holding after the end of its deadline, and would kill the other in less than an hour if its demands were not met, the Associated Press reported. The Taliban is also demanding the withdrawal of all German troops from Afghanistan. Insurgents kidnapped 23 South Koreans from a bus in southwest Ghazni province on Thursday in what was the biggest group of foreigners seized so far in the militant campaign to oust the government and its Western backers. "The kidnappers must release our people as soon as possible, and safely. In any case, valuable lives should not be damaged," Roh told a news conference in Seoul.