A federal law enforcement official said the information, released late last week, suggests "there is a new plan in the works" targeting New York, while a Homeland Security Department official said the nation's capital was also mentioned as a target, although from a different source.
Among the precautions New York police recommended Saturday to companies are:
- Consider posting a security officer at the fresh-air intake in HVAC rooms, if they are accessible to the public, and be sure the rooms are locked.
- They also suggested that companies challenge and identify maintenance workers when maintenance has not been requested, and watch for unanticipated deliveries.
- Post clear signs indicating restricted areas, and that persons caught trespassing will be arrested.
- Test alarm systems, and include doors to rooftops in the system. Authorities said that they are not aware of any specific attack time frames. The nation's threat level is at category "yellow," or elevated. But New York has remained at "orange," or high, since the September 11, 2001, attacks.