Updated

A New York City subway rider has hit a stranger in the face with a metal pipe and fractured his skull after an argument.

Police are looking for the attacker. The 59-year-old victim is hospitalized in serious but stable condition.

Police say it's unclear what sparked the argument, which happened Saturday night on a No. 2 train in Manhattan near the Chambers Street station.

Police have released video showing the two men seated as one gestures at the other, then stands up and gets into a swinging stance before the video stops. In an apparently later section of video, he puts the pipe on a hand truck and starts wheeling away. The other man appears to hold a hand to his head.

The attacker fled at the station.