A 10-year-old boy was slashed in the face during a fight inside an uptown housing project apartment, police said Saturday.

The woman who slashed the boy fled the apartment at Frederick Douglass Houses on West 104th Street shortly after the 2:37 p.m. incident and was being sought Saturday night, police said.

The victim was taken to Mt. Sinai Hospital.

“I heard people screaming, ‘Stop! Stop!” neighbor Felix Jean said of the dispute.

“He was always on his roller skates,” he said of the injured boy.

“You know, around in the hallway and playing with my kids sometimes.”

Another neighbor at the Manhattan Valley housing project, who asked not to be named, also heard the screaming.

“I have my own kids,” he said.

“It’s like, why would you do that to a child in general? There shouldn’t be any reason to slash a 10 year old. What could he have done to you?”