Police opened fire on a subway platform in Brooklyn during a confrontation with an alleged fare-beater, striking the man cops said was armed with a knife, two straphangers caught in the fray, and one of the firing officers, NYPD officials said Sunday.

One of those two passengers hit by the cops’ bullets, a 49-year-old man, was hospitalized in critical condition after he was hit struck in the head, according to the NYPD.

The two officers who opened fire were assigned to patrol the Sutter Avenue subway stop in the 73rd precinct when they spotted a man skip the station turnstile and walk through an open gate toward the train platform, Chief of Department Jeffrey Maddrey explained at an evening press conference from Brookdale Hospital.