A 21-year-old woman was allegedly raped and assaulted by five men near a park where she had reached to meet a friend in the hope of finding a job but was molested by him also, police said on Friday.

The incident took place in an isolated area in Sector 63 on Wednesday night and three of the five rape accused as well as the woman's friend have been arrested, Senior Superintendent of Police, Gautam Buddh Nagar, Vaibhav Krishna said.

The friend, a Class 7 passout, works as a peon in a local private firm and had fled the spot after he was assaulted by the group, leaving the woman behind, he said.

"The woman is illiterate and was in search of employment. She had reached the park to meet a friend who is also known to her brother. This friend had assured her help in finding a job and had asked her to meet him in the park, where he tried to rape her," Krishna said.

When a group of men present near the park saw the duo, they reached the spot and chased away the woman's friend after beating him up but then themselves took turns to rape her, he told reporters.

According to the officer, the victim approached the police after which an FIR was lodged at the Phase III Police Station and investigation taken up immediately.

He said that initially the five accused were unidentified but the police tracked them down and arrested three of them, while two are still at large.

"Four of the accused have been arrested. This includes the woman's friend and three from the group that raped her. Two accused are at large and will be held soon," Krishna said.

The three rape accused have studied till Class 5, 8, and 11, and were staying in shanties in Sector 63. They worked as hired labourers on a vegetable farm, the police added.

The FIR has been registered under Indian penal Code sections 376 (rape), 354 (Assault or criminal force to woman with intent to outrage her modesty) and 511 (Punishment for attempting to commit offences punishable with imprisonment for life or other imprisonment), the police said.

The police said the woman was sent for medical examination, while counselling by experts and legal assistance was also being provided to her.

All precautions were being taken considering the sensitivity of the matter, they said.

A reward of Rs 25,000 each has been announced for the arrest of the absconding duo, while a similar amount has been awarded to the local police for quick action in the case that has resulted in the arrest of the others accused, they said.