The FBI plans to tell Congress in a classified report next week that al-Qaeda still poses the most ”viable” terrorism threat to the United States, federal sources say. In its first-ever ”National Threat Assessment” report, the bureau also will give a detailed account of the capabilities of other terrorist groups and will identify the chemical and biological agents that U.S. officials believe are the most likely to be used in a terrorist attack, sources familiar with the report say. Details of the classified report are to be given to members of the Senate and House Intelligence committees in closed sessions Tuesday and Wednesday as part of a broader report by the CIA and other agencies about potential threats to the USA. Full Story