A city firefighter was arraigned yesterday on charges he acted as the “muscle guy” for a cocaine delivery ring that operated in South Brooklyn.

Anthony Ciliento pleaded not guilty to conspiracy and cocaine-trafficking charges in Brooklyn federal court before Magistrate Judge Roanne Mann.

Prosecutors say the 32-year-old bruiser served as the ring’s enforcer, breaking the nose of a drug-gang member who stole cocaine for personal use and then breaking a paintball gun over another co-worker’s arm.

Ciliento has been held behind bars at the federal Metropolitan Detention Center in Brooklyn since his arrest in August following a joint FBI-NYPD probe, officials said.

His attorneys are trying to convince a federal judge to release him on bail.