The incident occurred last night when the victim, a college student who hails from Enumamula village, was returning from Balaji Nagar area of Enumamula agricultural market along with her boyfriend, they said.
Police said the accused persons waylaid the duo and thrashed the boy before taking turns to sexually assault her.
A complaint was today lodged in Intezargunj police station in this regard, police said.
Four suspects have been detained and police are interrogating them.