An NYPD sergeant fatally shot an armed suspect in Brooklyn last night after the cop and another officer, as part of an anti-prostitution initiative, approached a car carrying four men, police sources said.

The cops, from the 76th Precinct, approached the vehicle near the Gowanus Expressway in Carroll Gardens at about 10 p.m.

Tyjuan Hill, 22, allegedly exited the car and fled, law enforcement sources said.

The two cops, part of “Losing Proposition,” which targets johns, chased after Hill, law-enforcement sources said.

When Hill allegedly pointed his gun at the cops, the sergeant fired once, striking him in the head, the sources said.

Hill was currently on parole and had served two years for robbery, police said.