A late night shooting at a midtown club in the Texas city of Houston killed three men and injured a fourth critically, the police said, just hours after another incident in which a police officer was killed with shots to the head.
On Twitter, police said the injured man was taken to hospital after the nighttime attack at the 2100 block of the city's Chenevert Street, but they did not immediately release further details or respond to requests for comments.
Media said a person with a gun entered the club and opened fire just before 10 p.m.
An affiliate of news broadcaster CBS quoted authorities as saying there might have been multiple gunmen, though it was not immediately clear if any were among the dead. It added that it was unclear if anyone had been taken into custody.
Earlier, a 41-year veteran of the force who responded to a disturbance call at an apartment in southwest Houston was shot multiple times and died, while another officer shot in the same incident was in hospital, the city's police chief said.