TSA issues warning that ISIS attack on US soil is imminent while FBI investigates the possibility. VIPR (Visible Intermodal Prevention and Response) teams are deploying to various undisclosed locations. ISIS frequently threatens to attack the US, this is the first time the US is responding as if it is a credible threat. A spokesman for the Department of Homeland Security declines to comment on specifics but states:
Over the last few months, we have made a number of security adjustments, including enhanced screening at select overseas airports and increasing random searches of passengers and carry-on luggage on flights inbound to the U.S., reflecting an evolving threat picture.