This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.NORTH RIVERSIDE, Ill. — Security is on high alert at North Riverside Park Mall after social media posts indicated a teenage flash mob could descend on the mall Saturday. The mall at 7501 W. Cermak Rd. in North Riverside has a weekend curfew of 6 p.m. for teenagers. On Saturday, that rule goes into effect at 2 p.m. as police and mall security brace for a possible flash mob. The Berwyn Police Department in a Facebook post described a flash mob as a group of people who organize “to form a sudden large assembly in a public place. Flash mobs can be organized for the purposes of entertainment, satire, artistic expression, or more troublingly, for engaging in rowdy and even criminal behavior.” In December, two people were arrested during a flash mob at the mall. On March 23, hundreds of teens descended on the mall and started fighting. The mall said it actively monitors social media pages because there have been so many past issues. This week, mall management saw social media posts encouraging teens to participate in a flash mob Saturday. Police will be upping security and restricting some entrances. Police have contacted local businesses and are asking residents in the surrounding area to make sure their homes and cars are locked.