New Delhi: Clashes broke out in JNU on Sunday night after the Left swept the students' union polls for the third year in a row.

President-elect N. Sai Balaji of CPIML-Liberation's All India Students Association (AISA) and teachers who came to his aid were heckled by unidentified persons at a police station where he went to complain of assault.

Police remain deployed at the gates and curbs have been imposed on gatherings on the campus.

In his complaint, Balaji said he called the police at 3.05am, around which time AISA activist Pawan Meena and former student Abhinay Sinha were assaulted by a group led by ABVP central working committee member Saurabh Sharma near Sutlej and Jhelum hostels.

When the police arrived and Balaji got into their vehicle for safety, Sharma allegedly forced the vehicle to stop twice and assaulted Balaji.

Sharma claimed that he and other ABVP cadres were defending themselves from "Leftist goons". The ABVP accused Balaji and other Left cadres of leading an attack.

The ABVP said in a statement: "Yesterday (Sunday) night, many ABVP activists were beaten up mercilessly inside their rooms. This began with Sujal Yadav being beaten up in his room around 2.45 am in the Jhelum Hostel by Pawan Meena and group... When Rajeshwar Kant Dubey and Mukul Khatri tried to save Sujal, they were also attacked by stones and rods."

The ABVP claimed that after the police left, Left supporters assaulted its activists, including a physically challenged student named Susheel Kumar. Two of them, the ABVP said, have suffered fractures.

Video footage shared by Balaji showed Sharma stopping a police van and leading a group with Russian language student Ashutosh Mishra in assaulting Sinha with footwear and plastic bottles. Sinha fell unconscious.

In the worst poll-related clashes in more than a decade, ABVP supporters fought with other groups during last week's presidential debate, and barged into the counting centre to protest against a decision to not allow its counting agents to enter late. Several students, including Meena, were treated for injuries suffered in clashes during the counting process on September 15.

After the ruckus at night, Balaji was taken to Vasant Kunj North police station around 4am. He said he was told to come back once the station house officer reached in the morning.

When he returned at 7am, Balaji alleged that Sharma and other ABVP cadres positioned themselves outside the police station and threatened to kill him. Around an hour later, a crowd began to gather at the police station.

"Every five minutes, someone would come to the waiting room and gesture at me and leave. When a friend came with breakfast for me, he said that around 100 people were at the station entrance. I called up my teachers, more than 20 of whom came in after 9.30am. The crowd barged in seeing them and demanded that I be handed over to them," Balaji told The Telegraph.

Cinema studies professor Ira Bhaskar told this paper: "When I went in around 9.45am, I saw a crowd outside. When I asked them why they were here, they said: ' Hamare bachche ko mara hai.' I saw a colleague who was with the crowd, along with some of our students. I asked him to calm them down and he said that 'if our boys are hit we will hit back'. I told him that as teachers our role is to calm people down and not encourage them to kill each other. One of the students, who I am told is with the ABVP, shouted at me and said that they would kill those who had hit them."