The incident took place in the early hours of Monday, May 30th, in a ginnel off Wells Street, Haslingden.
The victim, a 37-year-old woman was walking home at 1-20 a.m. after a night out and was approached by a man who asked her if she had a cigarette. She responded by saying no and then the man grabbed her and pushed her against the wall.
Having made off, the man gave chase and grabbed her again and forced her against a wall and touched her inappropriately before running off. He is described as Asian, in his 20s and with black, brushed-back hair.
An investigation has been launched and inquiries are continuing, with the victim able to formulate an Evofit of the possible offender.
Detective Constable Harvey Uppal said: “This is a nasty assault on a lone woman who was simply returning home from a night out.
“Understandably, this incident has left the victim feeling very shaken and nervous and it is important the person responsible is caught and brought to justice.
“We have an evofit of a man we would like to speak to in connection with this offence and I would urge the public to have a look at the image and see if they recognise him. If they do they should notify the police.”
Anyone with information is asked to call Lancashire Police on 0845 1 25 35 45 or call Crimestoppers anonymously on 0800 555111.