A high-level South Korean government delegation is now in Afghanistan trying to negotiate the release of the humanitarian workers, who are mostly women.
South Korea's Foreign Ministry said it is in touch with the captors of the kidnapped Koreans.
"Now we are contacting the militant group through a few channels, so we expect to get detailed information from there," Foreign Ministry spokesman Cho Hee-yong said at a news conference in Seoul.
Troops Surround Captors
Afghan officials have also said that talks are under way, through tribal elders and religious leaders, to secure the release of the Koreans.
Meanwhile, Defense Ministry spokesman General Mohammad Azimi told RFE/RL's Radio Free Afghanistan that Afghan forces have surrounded the area where the hostages are held but an attack has not been launched yet.
"The first stage of the operation which includes surrounding and blocking the region has started."
"An operation to rescue the kidnapped Koreans in the Ghazni Province has been launched by the national police, national army and coalition forces," Azimi said. " The first stage of the operation which includes surrounding and blocking the region has started. For the second stage of the operation which will include attacking the suspicious areas, the involved forces are waiting for [orders] from [higher authorities]."
The South Korean hostages were kidnapped by the Taliban in Ghazni Province from a bus traveling from Kandahar to the capital Kabul on July 19.
Though the Koreans are reported to be Christian volunteers, South Korean President Roh Moo-hyun said on July 21 they had no missionary intentions and were only providing free medical or educational services.
Taliban Extends Deadline
The Taliban said initially they would start killing the hostages if South Korea does not agree to pull its military engineers and medics from Afghanistan by July 22 in the afternoon.
However, Qari Yusof Ahmadi, who claims to speak for the Taliban, later said the militants are giving the Afghan and South Korean governments until 7 p.m. on July 23 to respond to their demand that 23 Taliban prisoners be freed in exchange for the Koreans' lives.
South Koreans To Leave By Year's End
The chief of the Korean parliamentary Defense Committee, Kim Sung-gon, said today that the country's 210 personnel in Afghanistan have started preparations to pull out of the country by the end of the year as planned.
South Korea's government stressed that the process had begun well before the Taliban demanded the withdrawal of the South Korean contingent from the war-ravaged country.
The Koreans are said to be the biggest group of foreigners seized so far by militants in Afghanistan.
Body Of German Found
Meanwhile, the AFP news agency quoted provincial police chief Mohammad Mazlum as saying today that the body of a German aid worker kidnapped in southern Afghanistan was recovered.
The body of the German was found in southern Wardak Province, where two Germans and five Afghans were kidnapped on July 18.
The Taliban said they had killed two German hostages on July 21. But German officials say they believe one of them is still alive.
"We must assume that one of the kidnapped Germans died in captivity."
"We must assume that one of the kidnapped Germans died in captivity," German Foreign Minister Frank Walter Steinmeier told reporters in Berlin on July 21. "Nothing points to murder, all signs tell us that he fell victim to the strain to which his kidnappers subjected him."
The fate of the Afghans captured with the Germans is not clear.
(with material from agency reports)