A man wearing a gas mask was filmed as he stormed a courthouse ... run through a metal detector amid chaotic scenes in the courthouse with people terrified at what was taking place.

Woburn District Court was evacuated Monday morning after a gas mask-wearing man allegedly walked ... also noting a Stoneham officer was transported from the scene for possible injuries.

A gas-mask-wearing assailant stormed into a Massachusetts courthouse Monday and unleashed a tirade, pepper-spraying officers and assaulting bystanders at random in a shocking, caught-on-camera attack.

WOBURN, Mass. (AP) — Police in a Boston suburb have arrested a man who they say entered a courthouse while wearing a gas mask and tactical gear and attacked several people with pepper spray.