Several Left-leaning activists were injured in a scuffle with policemen who sprayed water cannon after a DYFI rally turned violent on Wednesday.
The Democratic Youth Federation of India (DYFI), the CPI(M)'s youth wing, claimed that tear gas shells were also used to disperse the rallyists, a charge denied by police.
The DYFI called the rally demanding jobs and better price for crops for farmers.
ADG (Law and order) Gyanwant Singh said the organisation took out the rally without permission and its workers tried to cross the barricades set up by police.
"They also pelted the police with stones. We had to use water cannon to disperse them," he said.
The procession was supposed to reach from Air View More to Uttarkanya Bhawan, the state secretariat in North Bengal.
When police tried to stop the rally, the participants turned violent leading to a scuffle leaving several DYFI workers and three policemen injured.
DYFI cadres then staged a sit-in for some time.
Senior DYFI leader Sayandip Mitra claimed the police action was unprovoked.
"We were brutally beaten up while organising a peaceful agitation. She (West Bengal Chief Minister Mamata Banerjee) used to claim that democracy is under threat in India. Is this a sign of democracy in Bengal?" Mitra told reporters.
Senior TMC leader Gautam Deb alleged that Left parties in collusion with the BJP are trying to disturb the peaceful atmosphere of the state.
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