The kidnapping of three Japanese civilians by Iraqi militants will challenge Prime Minister Junichiro Koizumi's policy of supporting the United States, U.S. experts said Thursday.

William Odom, director of National Securities Studies at the Washington-based Hudson Institute, said Japan's international status will be hurt if it bows to the militants' threat to kill the hostages if Self-Defense Forces troops are not withdrawn from Iraq.

"When you get into a combat zone, you have to occasionally accept casualties and that may be what happens in this case," Odom said. "I can't advise the Japanese government on what to do and what not to do, but Japan's international status won't be improved if they do pull out."

Odom also said that if Japan decides to withdraw the SDF troops from Iraq, it could cause other countries "to be inclined to pull out at the first sign of danger."