This is the moment a terrified teenager punched her sex attacker to free herself after he grabbed her in the street.

Detectives released CCTV footage in a bid to catch the man who assaulted the girl, 13, in Blackburn, Lancashire.

The man can be seen following his victim before catching up with her and talking to her. She crosses the road away from him but he then sprints after her.

The suspect grabs his victim from behind before the brave teenager punches him and runs away.

He can then be seen running away from the scene at around 7pm on Wednesday 14 June, past a row of garden hedges.

The attacker is described as Asian, around 20 years old, with a slim build and black hair that was longer on top. He was wearing black-rimmed glasses.

Attacked: This is the moment a terrified teenager punched her sex attacker to free herself after he grabbed her in the street. Detectives released CCTV footage in a bid to catch the man who assaulted the girl, 13, in Blackburn, Lancashire

DC Lisa Bennett, from Burnley CID, said: 'This is a shocking incident where a 13-year-old girl has been sexually assaulted by a man who caught up with her as she walking along the pavement and began to talk to her.

'Thankfully she was able to fight the man off and run away. Our investigation remains on-going and we are really keen to hear from anyone who was in the area at the time or recognises the man pictured in the footage.

'It is vital that we trace this man and if you can help us with our enquiries, then please get in touch with us as soon as possible.'

Anyone with information can call police on 101 quoting log 1432 of June 14.