The Bihar girl, who came to Delhi for a medical treatment about five months ago, has been staying with her uncle.
One of the accused, identified as 21-year-old Sanjeev, abducted the girl, when she was standing outside the house, on Monday, Jan 25 and took her to his house.
He later invited two of his friends over and the three of them allegedly raped her in turns at knifepoint.
The victim has also revealed that the three culprits were planning on killing her but when she started screaming the neighbours rushed to the house and caught hold of two of the accused.
"A neighbour took the girl for a medical examination at a local hospital where sexual assault was confirmed. We registered a case and arrested the two," a senior police officer said.
The third accused, who is a minor, is absconding and the police have launched a search.