A police officer shot and killed a pit bull that had attacked three people in the Bronx Tuesday night, authorities said.

Cops responding to a report of a vicious dog inside a home on Timpson Place in Longwood around 3:45 p.m. discovered three people had been injured by the aggressive pit bull, police said.

The officer fired one round at the pooch, killing it, authorities said.

One of the three injured people, whose ages and genders were not immediately provided, was taken to Lincoln Medical Center with an injury to the right hand, an FDNY spokesman said.

No police officers were hurt.