A 19-year-old woman fought off a man who attacked her from behind in a Brighton street in the early hours of the morning.
Sussex Police said that the incident was being treated as an attempted rape.
The force said: “Police are asking for help tracing a man after a woman was attacked in Brighton.
“The 19-year-old victim was in St James’s Street when a man ran from behind her, grabbed her hair and assaulted her at about 2.50am on Friday 19 July.
“The victim bravely fought the attacker off and police are treating the incident as an attempted rape.”
Police want to speak to the man in the CCTV images about the incident.
The man was described as white, in his twenties, 5ft 4in or 5ft 5in tall and slim but muscular. He had short blondish or brownish hair which was flat and brushed forward at the front and he was clean shaven.
He was wearing a white short-sleeved top with a pattern over the front with possibly blue and red colouring in it.
Detective Inspector Lee Horner said: “This was a terrifying incident for the victim who did well to fend off her attacker but has been left shocked and hurt by what happened.
“We would like to speak to anyone who recognises the man from the CCTV footage or the description of the suspect.”
Anyone with information is asked to call Sussex Police on 101 or the independent charity Crimestoppers anonymously on 0800 555111.