Taliban insurgents have said Afghan President Hamid Karzai and U.S. President George W. Bush, meeting in Camp David on Monday, hold the key to ensuring the 21 remaining Christian Korean hostages currently held by the Taliban are released safely.

The Taliban said that the two presidents must agree to free jailed rebels or be responsible for the deaths of 21 Korean hostages.

The renewed Taliban threat comes as negotiations to free them remained deadlocked with no agreement even on where to hold talks between South Korean diplomats and the kidnappers.

The Taliban have killed two of the hostages and have repeatedly threatened to kill the remaining 18 women and three men unless the Afghan government agrees to free jailed rebels.

"Karzai has gone to America and it is possible he will take a strong decision with Bush to release the Koreans and agree to exchange prisoners because Bush and Karzai are responsible for securing the hostages," Taliban spokesman Qari Mohammad Yousuf told Reuters by telephone from an unknown location.

Asked what the Taliban would do if there is no swap, Yousuf said: "The responsibility will lie with Karzai and Bush."

However, Afghanistan has refused to release Taliban prisoners, saying that would encourage a kidnapping "industry".

"We will not do anything that will encourage hostage-taking, that will encourage terrorism," Karzai told CNN.

He added: "But we will do everything else to have them released."

Bush and Karzai are scheduled to focus on the worsening violence in Afghanistan and the threat from militant hideouts in neighboring Pakistan in talks at the U.S. presidential Camp David retreat.

Afghanistan is suffering the worst violence since U.S.-led forces toppled the Taliban after the September 11 attacks in 2001.

The Taliban campaign of kidnapping, ambush, suicide and roadside bomb attacks is aimed at convincing Afghans that Karzai and his Western backers are unable to provide them security.


TALKS DEADLOCK

The Taliban commander in Ghazni province, where the South Koreans were seized on July 20, said the provincial governor's accusation that Pakistani agents held the hostages was baseless.

"I am holding the 21 Korean hostages and I am personally guarding them and they were neither before, nor now, with Pakistani intelligence," Abdullah Jan Abu Mansoor told Reuters by satellite telephone.

"These statements have been issued only to malign Taliban mujahideen," he said. "The Afghan government should release Taliban prisoners. We don't have any links with Pakistan."

Afghan officials often accuse Pakistan of backing the Taliban in order to weaken its neighbor. Pakistan denies the charge.

South Korea has appealed to the United States and Afghan officials to negotiate the release. But South Korean diplomats have also met pro-Taliban Pakistani leaders and urged them to use their influence to save the group of church volunteers.

South Korea has also proposed holding face-to-face talks with the Taliban as a way of breaking the impasse, but a new apparent deadlock over where to hold the talks has emerged.

The Taliban have demanded the meeting in territory they control or under a United Nations guarantee elsewhere. But after four days of talks on talks, there were few signs of progress.

"Discussions are going on as to where they can meet," said Merajuddin Pattan, the governor of Ghazni. "We are trying to find a solution. Contacts between the Taliban and the Korean ambassador are going on over the phone," he said.

The Taliban said they were still waiting for the Koreans to reply to their conditions over a venue.

A U.N. spokesman said the international body had not received any request from the Taliban to supervise or guarantee talks.

The South Korean government is under intense domestic pressure to secure the release of the hostages, but Seoul has told the insurgents there is a limit to what it can do as it has no power to free prisoners in Afghan jails.

A day before the Koreans were seized, Taliban rebels in Wardak province, north of Ghazni, kidnapped two German engineers and five Afghans.

One of the Germans suffered a heart attack and was shot dead and one of the Afghans managed to escape. The rest are being held by the Taliban who are demanding Berlin withdraw its 3,000 troops from Afghanistan. Germany refused to do so.