BOSTON - A MAN stabbed a doctor while being treated at a psychiatric office at a Boston medical building on Tuesday and was fatally shot by an off-duty security guard who saw the attack, police said.

The attack took place in the afternoon at a high-rise affiliated with Massachusetts General Hospital.

The female doctor, identified by hospital officials as Dr Astrid Desrosiers, was in serious, but stable condition. Police said the suspect died of the gunshot wounds. He was identified as Jay Carciero, 37, of Reading.

The security guard was not affiliated with the hospital and just happened to be on the fifth-floor of the building where the attack occurred, according to Bonnie Michelman, the hospital's security director.

The attack took place at the Massachusetts General Hospital Bipolar Clinic & Research Programme, in a building near the main hospital.

The programme provides clinical care, conducts research and educates the community about bipolar disorder, according to its website. -- AP