BRIDGEWATER, Mass. (AP) — A Middleborough police officer has been injured during a police training exercise on Wednesday morning.

Bridgewater police responded to the regional training location to find an officer with a serious wound on his hand.

The officer, whose name has not been released, was treated on site and transported to Massachusetts General Hospital.

Officials say the officer was using a 37 mm projectile launcher loaded with training rounds when the device exploded in his hands.

The launcher is used regularly during SWAT operations for various purposes, including smoke screens and flares.

Investigators believe the device malfunctioned.