A pregnant woman is being treated in hospital after a man punched her in the stomach during a sexual assault.
The 21-year-old, who is seven months pregnant, suffered bruising during the incident on a derelict housing estate in Sheffield.
Hospital doctors are trying to assess whether her baby was injured in the attack.
The woman was walking along Kenninghall Drive in the Norfolk Park area of the city shortly after 1900 GMT on Monday when she was attacked.
A man who had just passed her in the street made indecent comments and then dragged her down a bank into a remote spot where he removed some of her clothing.
"She resisted and he punched her in the abdomen and tried to strangle her," the police spokesman said.
"She managed to kick him in the face while trying to break free."
The assailant fled when a passing car disturbed him.
He is described as mixed race, about 17 years old, 5 ft 5 in and wearing a blue, hooded tracksuit and striped hat.