Chicago police are alerting the public of a series of armed robberies on the Near North Side, including multiple cases involving groups who either attack or threaten violence against their victims.

The robberies took place in the area bordered by Elm on the north, Grand on the south, Michigan Avenue on the east and LaSalle on the west. They happened throughout the day, some early in the morning, others at night and at least one in the middle of the day.

In at least six cases since late August, police say groups of three to five suspects approached victims on the Near North Side and either attacked or threatened violence against them before taking their property.

But police say incidents like these are not confined the North Side. CPD Officer Michelle Tannehill said they’re investigating similar incidents in other areas as well.

“So everybody knows, we are at 20-year lows in robberies, and year-to-date we are down 18 percent,” Tannehill said. “We send out community alerts to combat robberies and it’s so those the community is vigilant.”

The description of the suspects are pretty vague, so police are asking anyone who may have surveillance video of any of the incidents to give them to police.