A SCHOOLGIRL was subjected to a frightening sex assault after her boyfriend was attacked and robbed in Bolton town centre.

Two men forced the 15-year-old girl against a wall before one of them sexually assaulted her.

Her 16-year-old boyfriend was helpless to intervene after being punched to the floor.

He had been repeatedly struck about the head, leaving him with cuts and bruises, before the thugs stole his £50 Nokia mobile phone.

The young couple had been out in Bolton on Sunday night before the attack in the early hours of yesterday.

The young couple were walking along Deansgate -- at the junction of Hotel Street, near to Marks and Spencers -- when the two men walked up to them at 3am.

Neither youngster has been named, but both are from the Kearsley area of Bolton.

They did not require hospital treatment, but detectives said they were both left "extremely shaken."

It is thought the girl managed to break free before the men ran off.

Det Con Bill Bimpson, of Bolton CID, described the men as dangerous and appealed for information.

He said: "The boy was punched about the head and had his mobile phone stolen. The young girl was then pinned to a wall and indecently assaulted.

"Both were left very shaken. It is a very nasty attack and both men need to be caught."

A passing woman found the youngsters in the road and took them to Bolton's central police station.

The boy has given a statement to detectives. The girl was due to give a statement today via a video link, because of her age, with her parents present.

She has been comforted by trained police officers and is recovering at home.

Both attackers are said to be aged in their 20s.

One is described as white, 6ft 3in tall, of large build with a bald head, black bushy eyebrows and blue eyes. He was wearing a black jumper and black trousers.

The second man is described as white, 6ft tall, with black closely-cut hair and brown eyes. He was wearing a white shirt and black trousers.

Anyone with information is asked to contact Bolton CID on 0161 856 5591 or Crimestoppers on 0800 555 111.