Shoe hurled at Kanhaiya Kumar in Hyderabad

The 28-year-old student leader, who has been camping in the city since Wednesday, said there were similarities between Delhi's Jawaharlal Nehru University and the Hyderabad Central University in the manner students and teachers wee being targeted.

Speaking at a seminar in Hyderabad, the JNU students' union president who was not allowed  on Wednesday  to enter the Hyderabad university where Dalit student Rohith Vemula committed suicide in January, said there was a "serious attack on universities".

"To say that students are losing control is unfair. How can the same thing happen in IIT Chennai, Fergusson, FTII? Why are campuses becoming warzones? We should ask the logical question that who is ordering the internal security to act this way," he asked, referring to unrest that has flared in university's across the country in the last few months.

On Tuesday, HCU witnessed violence as students attacked the media, threw stones at the police and surrounded for six hours the office-cum-residence of Vice Chancellor Appa Rao. He had returned to work on Tuesday after proceeding on long leave amid the furious protests that followed Mr Vemula's suicide in his hostel room in January.

Thirty four students and two professors were arrested and charged with vandalising the office of Mr Rao fuelling tensions.

Stopped from entering the campus,  Kumar, delivered a short speech at the university's main gates, alleging that students are being refused the right to dissent.

University officials said they had not granted permission for the event.