Police are appealing for witnesses after a teenage girl told how she was attacked by a man in a quiet country lane in Hornsea.
The girl has told specially-trained officers she was forced to the ground and indecently assaulted by the man as she waited for a taxi around 3am on Sunday morning.
The attacker ran away when the girl managed to fight him off.
Police cordoned off the lane near Burton Road, close to the viaduct on the Trans Pennine Trail, to search for clues while the girl was interviewed about the attack.
A Humberside Police spokesman said: "The victim was not hurt during the incident, however specially trained officers have spoken to the victim and are treating the incident as a sexual assault. At this stage, there is no description of the offender."
Officers are appealing to anyone in the Burton Road area of Hornsea who heard or saw anything suspicious between 3am and 5.45am on Sunday to contact Humberside Police.
They should call the non-emergency number 101, quoting crime reference number CS/1958567/2013.
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