An NYPD officer shot and killed a knife-wielding shoplifter in the Bronx on Saturday afternoon, police and sources said.

The deadly episode — which unfolded shortly after 2:30 p.m. in a 7-Eleven at East Tremont and Barkley avenues near the 45th Precinct stationhouse — may have started as an argument with a store clerk over a cigarette, or a “loosie,” sources said.

The man, 22, was in the store “acting suspiciously” with a knife, a 7-Eleven worker told cops at the nearby 45th Precinct.

The suspect allegedly charged at officers “with knife in hand,” and was shot near the entrance of the store.

Cops recovered the blade at the scene, the sources said. Officers gave first aid, police said, but the man did not survive.

“Seems like he was shoplifting and it was gone bad,” an NYPD spokeswoman said.

This is a developing story.