Three Americans and two other international troops were killed Friday in an attack in eastern Afghanistan, officials said. Insurgents attacked Afghan and international forces Friday with rocket-propelled grenades and guns, NATO forces said in a statement. The troops called in air support, forcing the militants to withdraw. They are being pursued, the statement said. Col. Greg Julian, a spokesman for US Forces in Afghanistan, confirmed that three of the dead were Americans. The nationalities of the other two were not immediately known because NATO typically waits for countries to release such information for their own soldiers.