GHAZNI, Afghanistan - Taliban rebels were running out of patience with talks over 23 kidnapped South Koreans, a spokesman said on Wednesday, but there was no word on the fate of the hostages after a rebel deadline passed.

Family members of the kidnapped South Koreans in Afghanistan wait for television news in Seoul July 24, 2007. The Afghan government and Taliban rebels are hopeful of a peaceful outcome to free 23 South Korean hostages held by insurgents, the two sides said on Tuesday. [Reuters]

Taliban spokesman Qari Mohammad Yousuf said earlier militants would start killing the Korean Christian volunteers unless the Afghan government freed a similar number of Taliban prisoners by 0930 GMT on Wednesday.

But he and other Taliban spokesmen were later not available for comment.

The warning came as a German journalist and his Afghan translator were kidnapped in east Afghanistan overnight. The Taliban seized two other Germans and five Afghans last week.

The kidnappings have made travel outside major cities risky for the thousands of foreign aid workers and United Nations staff in Afghanistan and may weaken public support for military involvement among the more than 30 nations with troops in the country.

"We had assurance from the Koreans that Kabul will release Taliban prisoners in batches and we will reciprocate," Yousuf told Reuters by telephone from an undisclosed location.

"We gave them eight Taliban names and they should have been freed by 7 p.m. (1430 GMT) yesterday, but nothing happened ...

"The Koreans should put pressure on Kabul on this, for there is the risk that at any moment, any time something can happen to the hostages. If by two o'clock today (0930 GMT), the Taliban are not freed, then some of them will probably be killed. Our patience is running out."

German Reported Seized

Both the Taliban and Afghan government officials had been hopeful of a breakthrough on Tuesday, with a Korean delegation negotiating through the mediation of tribal elders.

The Taliban are demanding Seoul withdraw its 200 troops from Afghanistan, something the South Korean government said it had planned to do at the end of this year in any case.

Afghan President Hamid Karzai has pledged not to swap prisoners for hostages after being heavily criticised for releasing five Taliban from jail in March in exchange for an Italian reporter.

The 23 Koreans church volunteers -- 18 women and five men -- were seized on the main road south from Kabul last week.

Two Germans were abducted in a nearby region a day before. One of them was found dead, apparently shot by his captors. The other is still being held.

The German reporter and his Afghan translator seized overnight in Kunar province in eastern Afghanistan were trying to reach a village in the Saangar district, where civilians were reported to have been killed in a NATO air strike two weeks ago.

"We had no knowledge of their arrival, they haven't met us, they haven't coordinated their trip, they should have come to me first, I would have arranged and facilitated his trip in Kunar," said a clearly angry Shalizi Deedar, governor of Kunar.

"They might have been taken hostage by some group for ransom, or by some people who want to benefit from the situation," he said. The Taliban have not taken responsibility for kidnapping the German reporter.

A search and rescue operation had begun, Deedar added.

The German weekly news magazine Stern said it was trying to get in touch with its reporter Christoph Reuter who had travelled to Afghanistan.

"He knows the country very well because he had been there again and again for Stern in the past few years and filed many reports. We are now very worried," it said in a statement.

The Taliban are demanding Germany withdraw its 3,000 troops from Afghanistan, something Berlin has flatly refused to do.