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Ghazni - Two women among 21 Koreans held by the Taliban in Afghanistan are seriously ill, a rebel spokesman said on Wednesday before the insurgents' 3:30 am EDT (0730GMT) deadline for Kabul to free prisoners in return for the hostages.

Taliban spokesman Qari Mohammad Yousuf said Afghan negotiators had not contacted the militants who have threatened to kill the hostages if the Afghan government fails to release a group of Taliban prisoners by the deadline.

"The majority of the hostages are ill, but two females are seriously ill and there is this possibility that they may die," Yousuf told Reuters by telephone from an undisclosed location.

Family members of the kidnapped South Koreans in Afghanistan cry during a news conference demanding for the safe return of the hostages in front of the US embassy in Seoul August 1, 2007. [Reuters]

He said the pair suffered from an unknown illness and the Taliban did not have the right medicines to treat them.

The Taliban were looking after the remaining South Koreans from a group of 23 Christians kidnapped from a bus in Ghazni province two weeks ago, he added. The Islamic movement killed two of the male hostages after previous deadlines expired.

Afghan officials have said no deal will be struck with the Taliban and demand the unconditional release of the remaining captives, 18 of them women.

President Hamid Karzai came under sharp criticism after releasing a group of Taliban prisoners in March in return for the freedom of an Italian journalist.

Rising Violence

The abduction of the Koreans comes after 18 months of rising violence in Afghanistan, the bloodiest period since the Taliban were ousted from power by US-led and Afghan forces in 2001.

A day before seizing the Koreans, the Taliban abducted two German aid workers and five of their Afghan colleagues in Wardak province which like Ghazni lies to the southwest of Kabul.

Family members of the kidnapped South Koreans in Afghanistan react during a news conference demanding the safe return of the hostages in front of the US embassy in Seoul August 1, 2007. [Reuters]

One of the Germans was found shot dead this week and one of the Afghans managed to escape. The other German and four Afghans were still being held.

The Taliban demand that Germany pulls its 3,000-strong force under NATO's command out of Afghanistan as the main condition for freeing the other German.

Al Jazeera showed a man against a rocky backdrop in a hilly area, a militant covering him with a rocket-propelled grenade.

The station did not play the sound of the video, but a presenter said: "The German hostage Rudolf B. ... urged Germany and the United States to pull out their forces from Afghanistan and urged his country to help save his life and secure his return to his homeland and family."

German Chancellor Angela Merkel has said Berlin will not give in to the kidnappers' demands.

Separately, the Taliban have killed four Afghan judges they kidnapped in Ghazni two weeks ago, a provincial official said on Wednesday. The bodies of the four, killed on Tuesday night, were found to the south of the town of Ghazni on Wednesday, he added.