OTTAWA, Ontario - Flash mobs have given way to "flash robs" where large groups of young people descend on a store and steal goods before leaving. Ottawa, Ontario, is the latest city to see recent activity of flash robs, CTV reports.

One Ottawa convenience store was robbed by a group of more than 40 youth, who came in waves before midnight, plundering $800 worth of food and damages. "What can we do?" questioned cashier Elias Dxafaii. "We cannot do everything. We can try to say to them, 'It's not good. You will be on the (security) camera.€™"

Another group targeted a supermarket recently. "Anyone in the store could have been hurt," said owner Tom Wilson. "Some of them started to knock products off of the shelves and actually break stuff. Once they heard the breaking sound, a lot of them just started to run, panic, and they left the store."

Police officials say flash rob groups use social media to designate a store, much like flash mobs do for a more benign purpose. "It€™s the use of social media and the ability to use technology to organize and gather," said Sgt. Murray Knowles, an Ottawa police officer.

The police are trying to catch the crooks at their own game, using Facebook and other social media to stay a step ahead of the flash robs.

Some retailers are going a step further and installing additional security measures, such as alarms that connect the store to the police, and having multiple cameras on site. "We put in all that, spend all the money to make sure it's safer for us and the employees," said Moe Atallah. He said he decreased the amount of space and product he has at his Ottawa convenience store to reduce the likelihood of being robbed by a flash mob.

Flash robberies have taken place in the United States as well.