The Taliban killed one of its 23 South Korean hostages on Wednesday, a local government official confirmed and said efforts were underway to secure the release of the rest.

"Yes, they have killed one of the hostages and efforts are underway to have the others released," district chief of Qarabagh district of Ghazni province, Khowja Seddiqi, told Reuters.

He did not give details.

Taliban spokesman Qari Mohammad Yousuf said earlier today that patience was running out in talks over the hostages and said rebel prisoners must be freed by 0930 GMT on Wednesday.

The warning came as a German journalist and his Afghan translator were kidnapped in eastern 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 pm (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 REPORTER 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.

"The pair were abducted in Saangar district of Kunar by the enemies of Afghanistan," said the local governor's spokesman Shah Wasi Mangal.

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