Police Chief BS Bassi, making it clear that he believes it is for the students to prove their innocence, said: "They should join the probe. If they say they are innocent, they should present evidence of their innocence."

The students - Umar Khalid, Anirban, Ashutosh, Rama Naga and Ananth Prakash - have been accused of organising an event at JNU or the Jawaharlal Nehru University on February 9 to mark the anniversary of the execution of terrorist Afzal Guru, during which anti-India slogans were raised.

Two days after the incident, Kanhaiya Kumar, the JNU students' union president, was arrested on sedition charges, for allegedly making anti-national statements. He is in Delhi's Tihar jail.

The other five students accused of seditious behaviour have denied that they did anything wrong.

"We went underground because we feared for our lives," one of the students told NDTV.

As they surfaced on the campus last night, they were joined by scores of students and teachers in a dramatic all-night sit-in as the police waited outside the gates.

Umar Khalid, who is accused of being the chief organiser of the Afzal Guru event, rubbished the charges against him as he addressed the gathering.

"For the first time in seven years, in the last 10 days, I was made to feel like a Muslim. I was reduced to my identity and it is shameful... These people are telling us about patriotism... They may have majority but they are scared of us... they are scared of our struggle, they are afraid of us because we think...,"Umar Khalid said to cheers from supporters.

JNU students and faculty members urged Vice Chancellor Jagadesh Kumar to back the accused students. "The students were in hiding because they feared mob-lynching and have returned when (they) believed that some normalcy has returned. We want the Vice Chancellor to take a stand like Jadavpur University that police will not come on campus," said students' union leader Shehla Rashid Shora.