The CPM condemned the violence by ABVP "goons" and denounced the Delhi Police.
Terming the violence outside Ramjas College in New Delhi as an example of "state machinery-backed violent intolerance", the CPM on Thursday demanded action against Akhil Bharatiya Vidyarthi Parishad (ABVP) activists involved in the assault and also against the police for connivance.
Wednesday's clashes between the RSS-backed ABVP and Left-leaning All India Students' Union (AISA) have injured over a dozen people.
The violence erupted a day after the ABVP forced the suspension of an event to be addressed by JNU student Umar Khalid, jailed last year for sedition.
Police have registered a case against unidentified persons for creating ruckus and assaulting public servants.
The CPM condemned the violence by ABVP "goons" and denounced the Delhi Police.
"This is another shameful example of the violent intolerance, backed by the state machinery of the RSS-BJP combine and its various wings, against all forms of democratic protest, particularly in universities," it said.
"Delhi Police played the shameful role of facilitator for the ABVP goons and stood by while the protesters were being stoned by them. Students and teachers, including from the Delhi University Teachers' Association and the Academic Council, who were marching to the local police station to protest, were attacked by the police," it said.
"The CPM demands that all those who indulged in violence to disrupt the seminar and attack the democratic protest should be arrested. Action must be taken against the Delhi Police personnel who connived with the ABVP," the party statement added.
Meanwhile, the Delhi Police have set up an inquiry into the conduct of its personnel.
Joint Commissioner of Police, Dipendra Pathak, said an inquiry had been set up under a senior police officer to look into reports of "inappropriate and unprofessional action" of some policemen. "We don't condone such action," he said, but also asked student protesters to make sure they stayed within the bounds of the law in future.