Police are looking for a male suspect after a woman was robbed and sexually assaulted in the Fort Richmond neighbourhood early Friday.

Police were called after a woman was heard yelling for help near the corner of Dalhousie Drive and Silverstone Avenue just after midnight.

The woman told police she had been walking in the area when a man approached, held a knife to her throat and demanded money.

Police say the man then punched the woman in the face and dragged her to a secluded spot in a lane where she was assaulted and grabbed in a sexual manner.

The woman was taken to hospital in stable condition, treated for minor injuries and released.

The assailant is described as a man in his mid-20s. At the time of the attack he was wearing all black clothing, with a tuque and scarf covering his face.