The Afghan government is doing all it can to secure the release of 22 South Koreans held hostage by the Taleban, President Hamid Karzai has said.
President Karzai assured the Korean envoy he was doing all he could
He assured a South Korean envoy that no effort was being spared on behalf of the Christian aid workers - mainly women - who were seized 10 days ago.
Mr Karzai said kidnapping foreign guests was "shameful", un-Islamic and against Afghan culture.
A Taleban spokesman said a new deadline had been set to kill the hostages.
Yousuf Ahmadi told AFP news agency that if the Afghan government did not meet its demands for the release of imprisoned militants by noon on Monday (0730 GMT), "the Taleban will kill some Korean hostages".
The group's leader, Bae Hyung-Kyu, was killed by the hostage-takers several days ago, but since then several deadlines have passed, apparently without further bloodshed.
The Afghan government has ruled out a prisoner swap.
Afghan officials reported no progress in efforts to secure the hostages by negotiation.
Mr Karzai told South Korean presidential envoy Baek Jong-chun that "he was personally involved in the process and that we are doing everything we can to secure the release of all the hostages," the visitor's spokesman said.
Pope Benedict said kidnapping contravened civilisation
Mr Karzai said the kidnapping of women, particularly, "will have a shameful effect on the dignity of the Afghan people", according to a presidential statement quoted by the Associated Press.
The sentiment was echoed by Afghanistan's national council of clerics, which said it was against the Prophet Muhammad's teachings.
"Even in the history of Afghanistan, in all its combat and fighting, Afghans respected women, children and elders," the council said.
Pope Benedict XVI also used his Sunday message to condemn the kidnapping, which he said contradicted "the most basic rules of civilisation".