A shootout erupted outside a Manhattan diner on 14th Street Tuesday during an argument, police said.

Two groups started shooting at each other shortly after 5 a.m. in front of the Good Stuff Diner near 6th Avenue, police said.

One of the groups allegedly involved was in the diner and the second group came in. An argument followed and spilled out onto the street. The details of the argument were not immediately clear.

A man in his 20s was shot in his chest and took himself to St. Barnabas Hospital in the Bronx, an official said. The man was not cooperating with police.