The city of Chicago announced on Tuesday that it filed a lawsuit against Glock, one of the most popular handgun manufacturers, accusing the company of endangering residents by continuing to sell firearms that can easily be turned into illegal machine guns.

The city is asking the Circuit Court of Cook County to block the sale of Glock pistols that can be modified, as well as a reasonable sum of money to compensate the city for damages from related gun violence.

According to the 41-page lawsuit , authorities in Chicago have recovered over 1,100 Glock firearms in the past two years that had been illegally altered with a quarter-sized modification called a switch or auto sear.

These auto-sears can be purchased online or manufactured using a 3D printer. They enable handguns to fire at up to 1,200 rounds per minute, the lawsuit states a rate as fast or faster than many fully automatic weapons used in the U.S military.