A Brooklyn summer basketball tournament turned violent last night, when three men were shot during intermission, sources said.

A gunman opened fire at a nonprofit tournament in Flatbush at Wingate Park on Kingston Avenue, around 10 p.m. yesterday.

The spectators, whose ages were not yet known, were shot in the leg, foot, and buttocks and taken to Kings County Hospital in stable condition, authorities said.

Organizers of the Bunkers Delight tournament, a nonprofit event held every year, believe alcohol may have fueled the violence.