Toronto police say a spate of recent GTA bank robberies are becoming increasingly violent with instances of bank staff being pistol-whipped, grabbed by the hair and put into chokeholds.

The robberies: June 1: Bank of Montreal, 5540 Lawrence Ave. E., Toronto.

June 15: Scotabank, 305 Port Union Road, Toronto.

June 22: Royal Bank, 75 Rylander Blvd., Toronto

June 25: 295 Eglinton Ave. E, Mississauga.

June 25: Royal Bank, 4022 Sheppard Ave. E., Toronto.

July 8: Royal Bank, 27 Rean Dr., Toronto.

July 11: 10098 McLaughlin Rd., Brampton.

July 22: Royal Bank, 6140 Highway 7, Vaughan.

Police say there have been eight similar armed bank robberies — including two on one day — since June 1.

Police say the robberies follow a similar pattern: the suspects storm into a bank branch brandishing handguns. One or more of the suspects then jump over the counter and head straight for cash drawers. Bank staff or customers that get in their way have been assaulted, in many cases violently.

"Our concern is the escalation of violence in these robberies," said Staff Insp. Mike Earl. "They jump over the counter and make a demand for cash. They’ve also been pistol-whipping tellers, pushing tellers, grabbing tellers by their hair. In one instance, grabbing a teller in a chokehold while demanding money."

The Canadian Banking Association has announced a $50,000 reward for information leading to an arrest in the robberies, citing a concern for the safety of bank staff and customers.

Security camera footage released

Police have also released a series of YouTube videos (see link below) that contain still images of the suspects captured by security cameras.

The robberies tend to happen at midday. In all cases, the suspects’ faces are covered by masks. They are also often wearing hooded sweatshirts. In some of the security videos, the suspects appear to be wearing similar yellow gloves.

Most of the robberies are carried out by two suspects but two robberies that happened on June 25 involved three suspects.

Five of the robberies happened in Toronto, and one each in Mississauga, Brampton and Woodbridge.

Police aren’t certain whether the robberies are related, though Earl said he believes there may be two groups of suspects.

Anyone with information is asked to contact police at 416-808-7350, Crime Stoppers anonymously at 416-222-TIPS (8477).