Police say a woman was sexually assaulted early Sunday morning inside an apartment building in Bed-Stuy.

NYPD detectives say it happened around 12:30 a.m. on Bedford and Willoughby avenues.

Police say an unknown person slapped a 27-year-old woman on the buttocks before following her into the building.

Authorities say the person then sexually assaulted the victim before leaving the building and the victim was taken to a hospital for treatment.

The individual then fled the location on an e-bike.

The NYPD is asking for the public's assistance in identifying the individual.

No arrests have been made as of Sunday night.