Gunfire erupted at a subway station in the Bronx early Saturday morning, but police say no one was injured.

Police responded to the 183rd Street station in the Fordham Heights section of the borough around 2 a.m.

Investigators collected four shell casings from the northbound 4 train platform, police said.

A man and woman believed to be in their late 20s fled the station. It wasn't immediately clear who fired the shots, but police said the rounds were fired into a train car.

The shooting comes days after a gunman opened fire on a northbound N train in Sunset Park, striking 10 people and injuring dozens more in the commotion.