An NYPD sergeant was injured while struggling with a suspect he was trying to arrest during a car stop in Chinatown, police sources said.

The cop and two other officers from PSA 4 were on patrol early Sunday when they saw 34-year-old suspect Gabriel Braciero allegedly make an illegal U-turn near the corner of Oliver Street and St. James Place around 3 a.m.

When the sergeant approached the car, he noticed Braciero was trying to hide something, sources said. The sergeant investigated and discovered two gravity knives and a set of brass knuckles under the driver’s seat, sources said.

When the cop attempted to take him into custody, Braciero fought back, causing him to suffer a separated left shoulder and a chipped elbow, sources said.

After subduing the suspect, the cops found a vitamin bottle in his pants pocket containing several packets of crack cocaine and loose marijuana.

The injured cop was treated at Beth Israel Hospital for his injuries, according to sources.