An alleged sex assault on a woman in Cowley in Oxford has prompted an appeal for information from police.

The incident happened between 2am and 3am on Thursday, when the 19-year-old was walking along East Avenue and was approached by two Asian men.

One of the men was described as aged in his late 20s, over 6ft tall, with a sharp, skinny face and short, black, spiky hair.

He had acne scars and crooked teeth and was wearing a blue T-shirt with yellow writing and blue jeans.

The other was described as having a round face, chubby and wearing a green T-shirt.

Det Con Nick Hills, of Thames Valley Police, who is leading the investigation, said: “During the assault a man ran up to the offenders and chased them down the street.

“Unfortunately he did not make himself known, so I appeal for him to contact police immediately as he could be crucial to our inquiries.

“I also appeal to anyone who was in Cowley in the early hours of Thursday and saw two men matching the offenders’ descriptions to get in touch.”

Anyone with information should call 08458 505505 or Crimestoppers on 0800 555111.