Free Republic

(CNN)The FBI is investigating a possible ISIS-inspired terrorist threat in the United States, law enforcement officials said Saturday. The investigation originated from intercepted chatter and other intelligence information that led officials to believe a possible plot could be in the works, the officials said. No arrests have been made. It's not clear whether the threat is real or aspirational. The exact nature of the threat couldn't be learned. One official said it focused on parts of California where officials stepped up security, a U.S. official said.

While the FBI investigates a possible ISIS terror attack on the basis of intercepted chatter and intelligence information, the TSA issued a classified warning that ISIS is planning an attack on U.S. soil. Little is known about the nature of the attack other than its imminence, which has prompted the TSA to deploy its new Visible Intermodal Prevention and Response teams, or VIPR, to various undisclosed locations. The VIPR teams include airports, train stations and other busy transportation hubs. One law enforcement source suggested parts of California were of special concern.