The Seoul government condemned the Taleban for the death of one of the hostages on Wednesday, and sent an envoy to negotiate the others' release.

However a Taleban commander called the abduction of foreigners, to be traded for Taleban prisoners, "a very successful policy".

Meanwhile, the US military said 50 Taleban fighters were killed elsewhere.

It said US and Afghan troops and US planes targeted a number of compounds in the southern province of Helmand during a 12-hour assault.

There is no independent confirmation of the report.

Increasing unrest

Afghan government officials in Ghazni province where the Koreans are being held confirmed on Thursday that the 22 hostages are still alive.

Following an increase in insurgent attacks, Afghan police have banned foreigners from travelling outside Kabul without their permission, Associated Press news agency said.

South Korean rallies have called for the release of the hostages

There have been increases in kidnappings, as well as clashes between Taleban and foreign troops, roadside bombings and suicide attacks in recent months.

After the mass kidnapping, South Korea banned its citizens from travelling to Afghanistan.

But the Taleban's military commander Mansour Dadullah told Britain's Channel 4 television that kidnapping would continue.

"Of course, kidnapping is a very successful policy and I order all my mujahideen to kidnap foreigners of any nationality wherever they find them and then we should do the same kind of deal," he said.

SAEMMUL COMMUNITY CHURCH Based in Bundang, on southern outskirts of Seoul One of a number of big Presbyterian churches in South Korea, with about 1,500 members Funds social programmes in Afghanistan, Pakistan and the Middle East Sends volunteers from the church to work on projects for short stints

Known for its emphasis on social work rather than evangelism overseasMr Dadullah himself was freed with four other Taleban members in exchange for a kidnapped Italian journalist earlier this year.

He also said he was in close contact with al-Qaeda.

'Inhumane act'

The 23 South Koreans were abducted in Ghazni, south-west of Kabul, one week ago.

The hostages - most of them women - are members of a Christian group doing aid work.

The body of one of the hostages was found with multiple bullet wounds in Ghazni province - where the Koreans are being held.

South Korea's foreign ministry identified the man as Bae Hyung-kyu, 42, a church pastor and leader of the group.

A statement from the office of South Korean President Roh Moo-hyun condemned the killing as an "inhumane act".

"Murder of an innocent civilian can never be justified.

"In consideration of such a grave situation, the government decided to despatch a special envoy to Afghanistan for closer consultations with the Afghan government," the statement said.

"We once again strongly urge them to promptly return home the Korean citizens taken hostage."

The Taleban said it would start killing the hostages if a deadline on Wednesday passed without their demands being met. However, a spokesman said on Thursday that the remaining hostages were still alive.

There was no way of confirming if that was true.

Baek Jong-chun, the president's chief security adviser, is to fly to Afghanistan on Thursday to work with the Afghan government to try to secure the hostages' release.