A threatened Taliban deadline to kill 21 South Korean captives passed without any harm done to them Wednesday, while a militant spokesman said the group was hopeful the Afghan government would release jailed insurgents.

The Afghan army dropped leaflets in the area where the hostages were being held, warning residents of upcoming military action. But the military said the mission was weeks away and wasn't connected to the hostages, denying media reports claiming a rescue attempt had been launched.

Qari Yousef Ahmadi, a purported militant spokesman, told The Associated Press after a noon deadline passed that the remaining 21 hostages were still alive.

The militants still wanted officials to meet their key demand — to release Taliban prisoners in exchange for the lives of the Koreans. He said two female hostages were very sick and could die from illness.

Ahmadi said earlier that eight prisoners had to be released by noon or more hostages would die. Several previous deadlines have passed with no killings, but two of the hostages have already died at the militants' hands.

Ahmadi said Mullah Omar, the Taliban's elusive leader whose whereabouts are not known, appointed three members of the Taliban's high council to oversee the hostage situation. Ahmadi said those three militants have the power to order the killings of the Koreans at any time.

Afghan National Army helicopters, meanwhile, dropped leaflets in Ghazni province — where the South Koreans were kidnapped and are being held — warning people of an upcoming military operation in the area.

Defense Ministry spokesman Gen. Zahir Azimi said the leaflets were dropped in order to avoid civilian casualties. "This operation has no relation to the Korean kidnapping case," he said.

The 23 South Koreans were kidnapped July 19 while traveling by bus on the Kabul-Kandahar highway. They are the largest group of foreign hostages taken in Afghanistan since the 2001 U.S.-led invasion that drove the Taliban from power.

Human Rights Watch, a New York-based rights group, called for the immediate release of all remaining South Korean captives.

The group said the Taliban have kidnapped at least 41 Afghan civilians so far this year and killed at least 23 of them. The rest remain missing.

"The taking of hostages is a war crime," Joanne Mariner of Human Rights Watch said in a statement.

In South Korea, relatives of the hostages made an emotional appeal to U.S. Embassy officials during an hour-long visit for help in negotiating their loved ones' release. The families were told their message would be passed on to Washington.

"We will hold on to any small hope to save them," Ryu Haeng-sik, 36, whose wife Kim Yoon-yong, 35, is one of the hostages, told The Associated Press outside the embassy in Seoul, his eyes red from weeping and fatigue.

"We cannot say we're relieved, but there is no other way but to believe their words, that they're going to do their best," he said.

Both the families and the South Korean government have asked that previous international practice in dealing with abductions be set aside in the interest of human life — effectively asking the United States to make an exception to its policy of refusing to make concessions to terrorist demands.

But the U.S. and other countries strongly criticized Afghanistan earlier this year when it released five Taliban prisoners to win the freedom of an Italian journalist held hostage.

The South Korean president's office said Wednesday that Washington was involved in efforts to win the hostages' release, but at a basic level.

"We understand their dilemma and limits," presidential spokesman Cheon Ho-sun said.

"There are some views that the United States holds (the keys to) everything. But that's a lot different from the fact," he said.

The South Koreans were members of the same church and had volunteered to go to Afghanistan's dangerous south against the government's advice.

Meanwhile, in Ghazni's Dih Yak district, police recovered the bodies of four Afghan men, one of whom was a local judge, who had disappeared a week ago while traveling from neighboring Paktia province, said Azizullah, a police official in Ghazni who goes by one name.

The police found the judge's ID card on his body. All four victims had bullet wounds, Azizullah said.