Katy Perry's Halftime Costume Scanned in Super Bowl Safety Bid

A look at the measures security experts take to keep the Super Bowl safe.

Officers will be wearing portable radiation detectors, and bomb-sniffing dogs will also be employed.

“Our challenges in Homeland Security are evolving. We have more concerns about domestic-based acts of violence, inspired by things people may see or read on the Internet,” Johnson said.

While Johnson said there are no credible threats against this weekend’s game, he said authorities are prepared to respond by any means necessary. That security involves a U.S. Customs Black Hawk helicopter, part of a fleet of aircraft guarding the Super Bowl from above. F-16 fighter jets will also be in the air.

Roughly 30 miles of airspace over the big game is restricted.