Police in Derry are looking for up to four men after reports of a serious sexual assault on a woman in the city.
The alleged incident happened at 12:30 a.m. when the woman was walking along North Edward Street.
She was attacked by up to four youths and dragged down an alley between Sackville Street and Great James Street where the incident is believed to have taken place.
Police have appealed for anyone with information to come forward.