North Riverside police and North Riverside Park Mall officials will step up security measures at the shopping center on May 11 after learning of a social media post calling for a flash mob that afternoon.

Police Chief Deborah Garcia said that the social media post, which was shared on SnapChat, went out two weeks ago. Since that time police are not aware of any other posts regarding a May 11 flash mob, but police are ramping up security measures as a precaution.

According to Garcia, North Riverside Park Mall will start imposing its youth escort policy at 2 p.m. on May 11 and they’ll have extra security guards in addition to two off-duty police officers stationed at entrances on the east side of the shopping center.

Round One entertainment complex, which experienced a serious incident on May 4, is stepping up its security efforts through the summer, said Garcia.

In addition to its regular security detail, three off-duty police officers will be working at Round One between the hours of 3 p.m. and 1:30 a.m. every Friday, Saturday and Sunday through the end of August.

The North Riverside Police Department will also deploy two additional police officers on May 11, Garcia said, and has sent out a critical reach message to surrounding departments to alert them to the potential for an incident that day.

North Riverside Park Mall has been targeted by flash mobs periodically in the last couple of years, and social media posts calling for large groups of teenagers to show up at the mall at a certain time and date have become commonplace, Garcia said.

Not all of those social media posts result in an incident, which make it difficult for police to predict when a flash mob might appear.

“We prepare and train, and this is what we can do,” said Garcia of the measures being taken for May 11. “We are prepared.”

Berwyn Police Chief Michael Cimaglia posted a message to Facebook on Friday morning reporting a possible flash mob on May 11 at North Riverside Park Mall. As teens have been removed from the mall during recent flash mob incidents, they tend to migrate east in large groups toward Harlem Avenue and Cermak Road, sometimes disrupting businesses in the North Riverside Plaza and Cermak Plaza shopping centers.

“Local Berwyn businesses are being contacted and given suggestions for how to respond if a large unruly group should present itself after being dispersed from the mall,” Cimaglia wrote. “For our residents, we highly encourage all parents to communicate with their children about the dangers of participating in such incidents, and discourage them from going to the mall unaccompanied without an adult.”