The U.S. military confirms four more American troops have been killed Thursday in Iraq.
That brings the number of Americans who've died this week in the fighting to 40.
More than 400 Iraqis have also died in the continuing violence in several parts of Iraq.
Radical Muslims are trying to put pressure on the U.S. and its allies by
kidnapping foreign civilians working in the country.
Hostage takers are threatening three captured Japanese civilians with death if Japan does not withdraw troops. Japan is vowing to stay.
Two Arab Israelis were also captured, along with a group of southern Korean Christian missionaries.
They were later released.