Police made a lathicharge and hurled stun grenades as the Bharatiya Janata Yuva Morcha (BJYM) activists tried to cross barricades placed in front of Cliff House, Chief Minister's Pinarayi Vijayan's official residence here, they said.
Water canon was also used to disperse the protestors who gathered in large numbers, demanding an NIA probe into the recent killing of the student.
The party workers, however, alleged police canned them and hurled the stun grenades without any provocation.
They said city police commissioner P Prakash assured them of an investigation into the lathicharge.
BJP and BJYM alleged that the activists of SDPI, the political offshoot of Popular Front of India (PFI), were behind the attack.
BJP state general secretary M T Ramesh urged the state government to hand over the investigation to NIA and invoke Unlawful Activities (Prevention) Act (UAPA) provisions against the accused in the case.
(This story has not been edited by Devdiscourse staff and is auto-generated from a syndicated feed.)