A pervert played with himself in front of two 4-year-olds and a teenager inside the elevator of an apartment building in the Bronx, police said.

The 17-year-old victim told police the man followed her and her two young cousins into a building near Grand Concourse and East 163rd Street and boarded an elevator with them on the evening of April 30.

Once inside the elevator, the man began masturbating, police said.

He then fled to an unknown floor.

Cops on Thursday released a video of the suspect, who is described as a black male about 25 years old, wearing an Orlando Magic baseball cap and white Nike sneakers.