A woman was grabbed from behind by a man who then put his hands over her mouth.
The incident, which officers are describing as ‘suspicious’, happened at around 10.30pm on Thursday in an area close to Fareham town centre which is known locally as the Gillies.
A 19-year-old woman, from Fareham, was walking along West Street and then through the Gillies.
Police say she was grabbed from behind by a man who she believes may have followed her after she passed him at a bus stop in West Street.
The man covered her mouth and she fell to the ground.
He then asked to use her mobile phone.
Det Con Wes Arnold, from Fareham police station, said: ‘This was an isolated incident and this time we do not know the motive as the victim was not threatened and the suspect did not use violence to steal anything.’
The suspect was white, in his early 20s, with an average build and about 5ft 9in.
He had short cropped blond hair and a local accent, and wore a mid-thigh length fluorescent jacket.
Det Con Arnold added: ‘I would appeal for anyone who was in the area of West Street or the Gillies at the time of the incident to contact police if they saw anyone wearing a fluorescent jacket or matching the description.’
Call Fareham police station on 101 or the Crimestoppers charity anonymously on 0800 555 111.