Four outsiders were nabbed from the JNU's North Gate in connection with the brutal violence unleashed on campus on Sunday evening and are being questioned, an official said.

The four, caught while fleeing the campus, were taken to Vasant Kunj police station for interrogation. 

Sunday evening saw several masked intruders barge into JNU campus and create havoc among students, mostly Left-affiliated students, assaulting them with sticks, metal rods and stones. The injured have accused the ABVP activists for the attacks, while the ABVP activists on campus have also pointed fingers at the Left student activists.

Both groups of students went to Vasant Kunj police station and lodged complaints with the police against the other group.

Meanwhile, police are awaiting medico-legal reports of those injured in the violence. At least 20 persons were taken to the hospital for injuries sustained in the violent attacks.

The campus has been volatile for the past few weeks over the controversial Citizenship Amendment Act, which grants citizenship to non-Muslim minorities of Pakistan, Afghanistan and Bangladesh.