A gunman has opened fire inside a hospital in the Bronx borough of New York, injuring several people, police say.
The man, said to have been dressed as a doctor and armed with a rifle, is now dead, they said.
The shooting began at about 14:45 local time (18:45 GMT) at the 1,000-bed Bronx-Lebanon Hospital.
Police identified the gunman as Henry Bello, a former doctor at the hospital. Reports say he killed himself.
Messages on social media spoke of doctors and nurses barricading themselves inside the building in the Mount Hope district.
The victims were reportedly shot on the 16th and 17th floors.
Associated Press news agency quoted one law enforcement official as saying one person had been killed by the gunman and six injured but this has not been officially confirmed.
The New York Police Department posted a tweet urging members of the public to avoid the area around the hospital at 1650 Grand Concourse.
The New York Times quoted a fire department official as saying that three doctors were among those shot.