Speaking at an event at the US Chamber of Commerce, Napolitano announced an expansion of the department's “If you see something, say something” advertising campaign, encouraging the reporting of suspicious behavior with a dozen new television and radio ads, along with announcements in public buildings and events.

The secretary said that the campaign is aimed at increasing public participation in preventing terror attacks as the country faces less risk from massive terror strikes than from smaller but harder-to-detect attacks.

The remarks echoed US President Barack Obama, who on August 17 warned against the threat of "lone wolf" terror attack by saying "the most likely scenario that we have to guard against right now ends up being more of a lone wolf operation than a large, well- coordinated terrorist attack."