Toronto police say a man was scratched in the face by a woman he attacked overnight.

A woman was walking north on Lansdowne Avenue from Bloor Street West at 3 a.m., when she was approached from behind and sexually assaulted.

The suspect fled the scene on foot, but police believe he "sustained scratches to his face" during the assault.

He is believed to be about 30 years old, five foot seven inches tall, with a stocky, athletic build. He had blond, or light red facial hair and was wearing a blue hooded sweatshirt and shorts.

Anyone with information is asked to call investigators at 416-808-7474, or Crime Stoppers at 416-222-8477.