"Today evening, two groups clashed with each other and some students are injured," a senior Delhi police officer told journalists. "The university administration has requested the police to enter (the campus)," the officer said, adding, "things are under control right now."
Sitaram Yechury, general secretary of the Communist Party of India, called the attack a "collusion" between the JNU administration and "goons" of a student group linked to Modi's Bharatiya Janata Party (BJP).
"It is a planned attack by those in power, which is afraid of the resistance provided by JNU," Yechury said.
An official at the All India Institute of Medical Sciences (AIIMS) in Delhi said that most of the injured at the hospital were undergoing treatment for "lacerations, cuts and bruises." "The brutal attack on JNU students & teachers by masked thugs, that has left many seriously injured, is shocking," tweeted Rahul Gandhi, a leading politician of the main opposition Congress party.
The incident is the latest in a series of violent clashes that have killed at least two dozen people amid protests over a controversial new citizenship law Modi's government passed in December.
The law allows New Delhi to grant expedited citizenship to minorities from three neighbouring Islamic countries who entered India by December 31, 2014, but critics say it marginalises Muslims in the country as part of Modi's larger Hindu nationalist agenda. The Delhi police last fought street battles with JNU students in November after protests broke out over fee increases at the top university.