A 12-year-old kid slashed a 9-year-old in East Harlem Wednesday, police said.

The victim told cops he was in the courtyard at 1680 Madison Avenue playing around 5 p.m. when a boy named Brandon came toward him and said, “I’m going to cut you,” according to police sources.

The older boy then cut him on his left hand.

The younger boy was taken to Mt. Sinai Hospital for treatment.