Police are appealing for witnesses after a woman was raped in Bicester.
The woman, aged in her 20s, was attacked while walking along Kingsclere Road between 05:00 and 06:00 GMT on Sunday, Thames Valley Police said.
The man responsible was described as being in his 20s, of a muscular build, with shaved hair and about 5ft 10in tall.
Police said when he approached the woman he was believed to have been with two other men.
The victim is being supported by specially-trained officers and police have increased patrols in the area.