Troops killed at least 75 militants in three separate battles in southern Afghanistan.

The apparently positive development came as the Islamic rebel group said that a German captive who was abducted separately from the Korean Christian aid workers was very sick and was drifting in and out of consciousness.

The rebel group has called for both Berlin and Seoul to pull their troops out of the war-battered country and for the release of 33 insurgents held prisoner by Afghan authorities in exchange for the hostages.

"We've established direct contact with the South Korean delegation through tribal elders," Taliban spokesman Yousuf Ahmadi told AFP by telephone from an unknown location.

"We hope this time the talks have a result," he said.

A deadline set by the Taliban, after which they say they will start killing the South Koreans, expires at 1430 GMT. The rebels, remnants of the hardline regime toppled by US-led troops in 2001, have already extended it twice.

The delegation led by the South Korean ambassador to Kabul arrived Tuesday in the southern province of Ghazni where the hostages are being held, said provincial police chief Alishah Ahmadzai, who was also involved in the talks.

Seoul sent a crisis team into the country on Sunday to push for the release of its captive nationals, most of whom are female.

Nearly 1,000 Afghans slammed the Taliban for the "un-Islamic" abductions in a protest in the southern town of Ghazni, the provincial capital.

"We demand that the Taliban free the hostages as soon as possible. Their acts are against our beloved Islam and our respected culture," said one demonstrator, Mir Mahfooz.

The bullet-riddled body of one of two German hostages seized separately from the Koreans last week was found on a road on Sunday, and the Taliban spokesman said the second was now drifting in and out of consciousness.

"The German is very badly sick. He has got diabetes," Ahmadi said. It was impossible to verify the claim independently.

Meanwhile, in southern Helmand province, Afghan troops ambushed by militants called in airstrikes and fought back with small-arms and mortar fire, the US-led coalition said. The coalition said at least 36 insurgents were killed in the fighting Monday, but no Afghan or coalition troops were hurt.

In Uruzgan province, police clashed for three days with militants blocking the road leading to Kandahar province, leaving 26 militants and two policemen dead, said Wali Jan, the Uruzgan deputy highway police chief. Nato-led and Afghan army troops joined the battle Tuesday, reopening the road for civilians traffic, he said.

Another 13 suspected militants were killed in Kandahar province, the Defence Ministry said.

The battles took place in remote and dangerous parts of Afghanistan, and the death tolls could not be independently confirmed.