Two women were shot outside a West Harlem public housing project overnight, police said.

The victims, ages 35 and “around 19 or 20,” were both struck in the arm when gunfire erupted Friday at 11 p.m. in front of the Frederick E. Samuel apartments, a NYCHA building on West 147th St., cops said.

The women were taken to Harlem Hospital in stable condition, police said.

Four men wearing black ski masks are wanted for the shootings. They were last seen heading eastbound on West 143rd Street, authorities said.

The motive for the shooting is unknown, cops said.

“We don’t know if they were targeted,” an NYPD spokesman said Saturday.