A deadly shooting in Pennsylvania’s York County left three police officers dead and two others critically injured on Wednesday. The gunman was also killed in return fire from law enforcement.

The incident occurred around 2 p.m. local time near a school in the small town of Spring Grove, about 100 miles east of Philadelphia. Authorities said the assailant opened fire indiscriminately at police officers, killing three on the spot.

Police quickly returned fire, neutralizing the attacker. The injured were airlifted to a hospital by helicopter.

Pennsylvania’s governor assured residents that the town of 2,500 people faces no immediate threat, while investigations into the motive and details of the attack are ongoing.