The Taliban extended its deadline to 1130 GMT for 22 South Korean hostages they are threatening to kill after an appeal by Afghan negotiators, a Taliban spokesman said, adding all of the remaining captives were alive.

"Because of the team's requests ... the Taliban have extended the deadline to 16:00 local time," Qari Mohammad Yousuf told Reuters by phone from an undisclosed location.

The Taliban had earlier set a 0730 GMT "final deadline", after which they said they would kill the 22 Koreans -- mostly women -- unless the Afghan government freed jailed rebels.

Monday's first deadline was issued by the Taliban leadership council, led by elusive Taliban chief Mullah Mohammad Omar, giving the threat to kill the hostages more weight than several other deadlines that have passed without incident.

The Taliban seized the Korean Christians more than 10 days ago from a bus in Ghazni province to the southwest of Kabul and killed the leader of the group on Wednesday after an earlier deadline passed.

That prompted the Afghan government to seek more talks with the Taliban, who said the release of a group of militants held by Kabul was the only way out of the crisis.

On Sunday, the Taliban ruled out holding further talks after they said government negotiators demanded the unconditional release of the hostages and a senior Afghan official said that force might be used to rescue them if talks failed.

The Afghan government had wanted the Taliban to first release the 18 women hostages, but the insurgents demanded the government release its prisoners first, leading to deadlock, a Kabul-based Western security analyst speaking on condition of anonymity said.

President Hamid Karzai has remained silent throughout the hostage ordeal, except for condemning the abduction, the largest by the Taliban since U.S.-led forces overthrew the movement's radical Islamic government in 2001.

He came under harsh criticism for freeing a group of Taliban in March in exchange for the release of an Italian journalist.

The abduction of the Koreans came a day after two German aid workers and their five Afghan colleagues were seized by Taliban in neighbouring Wardak province.

The body of one of the Germans has been found with gun shots and the Taliban still hold the other along with four Afghans.