Four people have been killed and at least 15 injured in a shooting rampage at a US health club.
Pittsburgh television station KDKA said the killings were at the LA Fitness Centre in Bridgeville, a community of about 5,000 not far from central Pittsburgh and Pittsburgh International Airport. The gunman was among those killed.
UPMC Mercy Hospital said five critically injured women were taken there.
Witnesses told US networks that a man turned off lights and shot people in a Latin dance class in the aerobics center of the gym at approximately 8 p.m..
Allegheny County police said a person called them and said someone was shooting inside.
A witness told the Pittsburgh Post-Gazette newspaper she was in an exercise class when a man came in through a back door and started shooting.
Gym member Lauren Dooley said she heard 12 to 15 shots.
Perry Calabro, who was playing racquetball inside, said when the shooting began "everybody started running".
Another witness said: "He got off a lot of shots. People everywhere were screaming. It was horrible."
Allegheny General Hospital spokesman Dan Laurent said two women with gunshot wounds had been taken there.
A spokesman for the LA Fitness chain said: "Each of us in the LA Fitness family are shocked and saddened by the senseless acts of violence that took place. . . this evening. Our thoughts and prayers are with the victims, their families and friends. We are working with local law enforcement as they conduct their investigation."
View LA Fitness in a larger map