The Department of Homeland Security said it is expanding its "If You See Something, Say Something" public awareness campaign to Charlotte, N.C., just as that city prepares for the global spotlight that the Democratic National Convention will bring in September.

The program, announced by Charlotte Mayor Anthony Foxx and other local officials Monday at the NASCAR Hall of Fame in Charlotte, will post billboards in the transit system, in public buildings and on the city's website urging citizens to report suspicious activity to police. DHS will also run 30-second public service announcements on local government access TV.

The roll-out comes as activists who protested this week's NATO meeting in Chicago announced they would head to Charlotte to make their voices heard. They will join hordes of Occupy Wall Street protesters who plan to camp out during the convention and air their grievances to gathering Democrats.

The public safety campaign originated in New York, where in 2010 an eagle-eyed T-shirt vendor tipped off police to a suspicious vehicle and helped foil a plot to bomb Times Square.

Monday's announcement made no mention of the Democratic National Convention, which starts Sept. 3, but it wouldn't be the first high-profile event to feature the publicity campaign. Safety messages were televised and included in game programs and fan guides for this year's Super Bowl in Indianapolis.