A clash erupted on Friday between the police and members of Left-affiliated students organisations who were marching to the State Secretariat.
The protesters had organised a march to the State Secretariat to protest against rampant unemployment.
The activists had collected lakhs of job applications from across the State and wanted to give it to Chief Minister Mamata Banerjee.
Violence started a few kilometres from the Nabanna building when police personnel lobbed tear gas shells, resorted to baton charge, and used water cannons to disperse the crowd.
Witnesses reported seeing several injured and bleeding protesters.
Some of our students were seriously injured. They were protesting for the right to work and stood against disproportionate display of brute force by the police. I salute them, Communist Party of India (Marxist) leader and Polit Bureau member Mohd. Salim said.
He also ridiculed the Didi ke Bolo campaign launched by the Trinamool Congress where people can call up the Chief Minister with their grievances. The CPI(M) leader said that when students want to meet and give deputation to the CM they are met with brute force.
The CPI(M) claimed that over 60 supporters were injured and some had to be hospitalised. The police said that five of their personnel suffered injuries.
Earlier this week, violence had erupted when BJP supporters marched to the Calcutta Electric Supply Corporation HQ in Esplanade demanding a reduction in power tariff.