The incident occurred last night in a field at Old Mall Colony when the girl, an intermediate student, had gone there to answer the nature's call, they said.
A case was registered today against Venkatesh, Chinna, Shanker and Vijay under Nirbhaya Act after the girl lodged a complaint, said Yacharam police station inspector J Madan Mohan Reddy.
"The four accused were taken into custody and are being questioned," he added.