An armed female followed a 29-year-old woman into a Harlem building lobby and shot her in the leg Tuesday night, cops said.

The bullets flew inside 123 West 135th Street around 10:15 p.m. when the unknown gun-woman fired two shots in the lobby. The shooter, who was described as a female dressed in all black, fled the scene.

The victim was taken to Harlem Hospital in stable condition.

It wasn’t immediately clear whether the women knew each other and it appeared that nothing was stolen from the victim, a police spokeswoman said.