WASHINGTON DC: Three police officers were shot dead and two others critically injured during a “domestic-related” investigation in Pennsylvania, authorities confirmed.

Pennsylvania State Police Commissioner Colonel Christopher Paris said the gunman was killed in an exchange of fire with officers.

The shooting took place shortly after 14:00 local time (18:00 GMT) in Spring Grove, a small town with a population of around 2,500.

Images from the scene showed an injured officer being airlifted by a medical helicopter. As a precaution, a nearby school district went into temporary lockdown. The district later clarified that the school itself was not directly affected by the incident.