BLOOMINGTON (AP) - The Mall of America has provided a rare glimpse at some security measures in an effort to calm fears over an online video purportedly made by a terrorist group urging extremists to attack shopping malls in Western countries.

The Bloomington megamall is the nation's busiest shopping center with 40 million visitors each year. The steps taken behind the scenes to keep visitors safe are generally unknown to shoppers.

Family-friendly dogs trained to sniff out bombs patrol the mall with officers. A security team stationed at a nerve center keeps watch on hundreds of security cameras throughout the shopping center. Delivery trucks are swabbed for explosives before merchandise in unloaded.

Mall officials say most safety measures have long been in place, but that it's stepped up security following the threat.