PHILADELPHIA (AP) — Authorities say an early morning shooting outside a Philadelphia nightclub wounded at least six people, one of them critically.

Police said a man opened fire shortly before 3:30 a.m. Sunday at a crowd outside Trilogy nightclub in the Northern Liberties neighborhood north of the center of the city.

Police said a 26-year-old woman hit in the chest was taken to Jefferson Medical Center in critical condition. Two 30-year-old women and a 31-year-old woman were listed in stable condition as were a 29-year-old man and a 37-year-old man.

Capt. John Walker told reporters that an argument that began inside the club continued outside and escalated into a fight, and one man opened fire on another man, hitting him and the other victims.

No arrests were immediately reported. Police said a man who showed up at a hospital with a gunshot wound and an injured person spotted on gas station surveillance video may have been victims in the same incident.