Police in Detroit say four people were injured after an argument escalated into gunfire in downtown Detroit.

Police say the shooting happened early Tuesday in the city's Greektown area after people talking in an alleyway that's also used for parking started to argue and two of them apparently pulled weapons.

Three of the injured were listed in critical condition and one was in stable condition. Police say one of them was believed to be a possible shooter.

Investigators have reviewed surveillance video and say they're looking into what the argument was about. Names of those involved weren't immediately released.