BROOKLYN - Police are investigating a string of armed robberies across the city, including at least three in Brooklyn. 

Investigators say that in each case, the suspects pull out a gun and demand cash or merchandise. Most recently, they held a gun to an employee at a pharmacy on Broadway in Bushwick on April 24, and got away with about $100 and prescription drugs. 

Just 10 days before that, cops say the men hit up a liquor store on Prospect Park West, nabbing about $1,400. Earlier that same day, they stole about $6,000 worth of eye glass frames and cash. 

Police have released surveillance videos and a photo captured during armed robberies in Manhattan, which they believe are connected. They say that in six of the seven reported incidents, there were two men involved, but a third man joined them once. 

No one was hurt during any of the crimes, but on one occasion, one of the suspect fired a gunshot into a wall. 

Anyone with information is asked to call Crime Stoppers at 1-800-577-TIPS