A 16-year-old Brooklyn student was stabbed in the stomach outside the Atlantic Avenue subway station on Monday afternoon, police sources said.

The unidentified teen was knifed outside 139 Flatbush Ave. after a fight erupted among a group of schoolkids around 3:30 p.m., according to sources.

An officer who arrived at the scene was maced during the brawl and transported to Brooklyn Hospital.

Cops arrested three people and charged one person in connection with the stabbing, sources said.

The victim suffered non-life threatening injuries and was also transported to Brooklyn Hospital.