The shooter turned the gun on himself before 3 p.m., police Lt. Tom Robinson said.
One of the shooting victims was in surgery, Robinson said. Information on the condition of the others wasn't immediately available.
The shooter's motives were not immediately known.
Nevada Department of Public Safety spokeswoman Gail Powell said the incident has been "contained."
Gov. Brian Sandoval said on Twitter that he and his staff were monitoring the situation and his thoughts and prayers were with those affected by the tragedy.
The Renown Medical Center is the largest hospital in northern Nevada.
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