Preventing law enforcement authorities from having access to encrypted communications would make it easier for sympathizers of Islamic State militants to carry out an attack in the United States, FBI Chief James Comey said on Wednesday. The Federal Bureau of Investigation is pushing technology companies to let law enforcement authorities have access to encrypted communications to investigate illegal activities. Comey told a U.S. Senate Judiciary Committee hearing that Islamic State, also known by the acronym ISIL, is imploring supporters through Twitter to carry out attacks.