Fifteen US embassies in Europe have received letters containing a suspicious white substance and tests have show 14 of them to be harmless, State Department spokesman Robert A. Wood said Wednesday. Test results for the substance in one of the letters have not yet been received, he said. U.S. authorities also said suspicious packages have been sent to National Guard bureaus and reserve facilities in 36 states. An internal Dec. 16 report from the Department of Homeland Security said the 51 packages included anti-war compact discs, and one package also had a suspicious powder. It said the powder, sent in a package to Utah's National Guard headquarters, was tested and found not to be toxic. Civilians who train one month and on weekends make up the National Guard, military units that can be mobilized for domestic emergencies such as floods or activated for service in Iraq and Afghanistan.