A U.S. official says Washington is doing all it can to pressure Taleban kidnappers who are holding 21 South Korean hostages in Afghanistan. The United States has so far limited itself to making public statements calling for the hostages to be released, but as VOA's Stephanie Ho reports, the official did not rule out the possibility of using military force.

U.S. Assistant Secretary of State Richard Boucher said the United States is very concerned about the fate of the South Korean hostages in Afghanistan, and has been in consultations with the South Korean and Afghan governments to secure their release.

"We are working very closely with the Korean government and with the Afghan government to try to make sure the pressure and the focus remain where they should be, and that's on the Taleban, who are the ones who have done this terrible thing," he said.

Boucher said Washington's efforts to exert pressure so far have largely consisted of repeatedly and publicly calling on the Taleban to release the South Koreans. He did not say whether anything more concrete is being done, but indicated that future efforts may include a military option. "There are both things that we say, things that others say, things that are done and said within Afghan society, as well as potential military pressures," he said. 

These comments come amid South Korean appeals to the United States for help securing the release of the hostages through negotiations. They also appear to contradict a South Korean official's remarks, following a meeting on the sidelines of a regional summit in Asia, that U.S. and South Korean officials have ruled out the use of force to free the hostages.

The kidnappers already have killed two Korean hostages, and the Taleban says any rescue attempt will jeopardize the lives of the remaining hostages. The group is demanding Kabul release Taleban prisoners in exchange for the captives. The Afghan government says it will not trade prisoners for hostages, a position the U.S. government supports.

Meanwhile, South Korean lawmakers consulted Thursday with U.S. officials in Washington, and an official South Korean delegation is in Afghanistan to meet with the Taleban kidnappers.

The issue is expected to be near the top of the agenda in talks between President Bush and Afghan President Hamid Karzai, when they meet Sunday and Monday at the Camp David retreat outside of Washington.