South Korea and the United States agreed not to use force to free 21 Korean hostages in Afghanistan on Tuesday, but Afghan troops warned villagers of a possible offensive in the area where the captives are held.

Afghan policemen discover body of the second Korean killed by the Taliban outside Ghazni city south of Kabul July 31, 2007.  [Reuters]

The Taliban kidnapped 23 South Korean church volunteers in Ghazni province, southwest of Kabul, two weeks ago and have killed two of them. The hardline Islamist guerrillas have said they will kill the rest unless their jailed comrades were freed.

South Korean Foreign Minister Song Min-soon and US Deputy Secretary of State John Negroponte met on the sidelines of a regional security forum in the Philippines on Thursday.

"They agreed that both countries will not use any kind of force," said a South Korean diplomat after the meeting.

The body of Shim Sung-min, 29, the second South Korean hostage shot dead by Taliban militants is expected to arrive home on Thursday. His family said it would hold a funeral and then donate his remains for medical research.

The remaining 21 hostages are still alive, a Taliban spokesman said on Wednesday, but warned they might be killed if the Afghan government does not free insurgent prisoners.

The government has refused to give in to the demand, saying that would only encourage further abductions.

The Taliban have also warned that any attempt to rescue the hostages by force would put the captives' lives at risk.

The Defence Ministry said army helicopters had dropped leaflets in several districts of Ghazni province on Wednesday warning residents to move to secure areas to avoid casualties during an operation to be launched in the "coming weeks".

But the ministry said it was a routine operation not linked with the kidnapping. Both Afghan and foreign troops were stationed in the area, a local official said.

APPEAL FOR US HELP

Any rescue operation would be fraught with danger as the Taliban have split the hostages into small groups and are holding them in several locations in the mainly flat but lush region.

South Korean parliamentarians left for the United States to persuade Washington to help end the standoff. The eight lawmakers hope to speak to US and UN officials "to appeal for the quick and safe return of our people in Afghanistan", they said in a statement.

The South Korean government is under intense pressure to bring the captives home, but the power to meet the key Taliban demand -- the release of rebel prisoners -- lies with the Afghan government, which has so far refused to give in.

Seoul has called for "flexibility", a comment analysts say is directed at the United States to sway the Afghan government to strike a deal with the kidnappers.

The United States insists it does not make concessions to terrorists. But lawmakers are hoping Washington might make an exception to help bail out an ally that has sent troops to Afghanistan and Iraq.

South Korea's two largest conservative dailies said such visits might stir anti-US sentiment if the ordeal deteriorates even further and could hurt negotiations on freeing the hostages.

"Anti-American sentiments by some elements are only helping the Taliban and justifying their atrocities," the Chosun Ilbo, the country's largest newspaper, said in Thursday's editorial.

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

One German was found shot dead and one of the Afghans managed to escape. The other German and four Afghans are still being held. The Taliban have demanded Germany pulls its 3,000 troops out of Afghanistan in return for freeing the other German.

Berlin has rejected the demand.