South Korea expressed hope Friday that an upcoming summit between the United States and Afghanistan would help efforts to win the release of 21 Korean hostages from Taliban captivity, according to AP. Afghan President Hamid Karzai is to make a weekend visit to the United States to meet with U.S. President George W. Bush, with the agenda of their talks expected to include the hostage crisis. South Korea has asked Washington and Kabul to exercise «flexibility» in handling the crisis, as negotiations to free the captives are deadlocked over the Taliban's demand that insurgent prisoners be freed. «The Afghan and U.S. governments ... have a certain level of involvement in this issue,» South Korean presidential spokesman Cheon Ho-sun said in a regular press briefing. «We have expectations that the two leaders would have sufficient understanding of our position when they hold a summit.» The Taliban insurgents kidnapped 23 South Koreans from a bus in southern Afghanistan on July 19, and have since killed two men as their demand for a prisoner-hostage swap was not met. The captors have threatened to kill more. The United States has said it remains in contact with the South Korean and Afghan governments on the issue, repeating its principle of refusing to negotiate with terrorists. That prompted criticism in South Korea that Washington is not doing enough, but the president's office here sought Friday to defuse such remarks. «The U.S. is providing maximum support in all areas actively,» Cheon said. «Our position is that this is not an issue that should lead to anti-Americanism.» Senior South Korean lawmakers are in Washington to ask the U.S. government to soften its no-negotiation stance. State Department spokesman Tom Casey said Thursday in Washington that the U.S. maintained contacts with South Korean and Afghan governments, adding «we are all going to do whatever we can to see that these individuals are released unharmed and allowed to go back to their families.»