A peace rally led by Left Front chairman Biman Bose apparently ran into resistance by law enforcers in Howrah's Salkia on Monday, prompting the CPM veteran to stage a sit-in against "police excesses".

As tension erupted when the rally was barely 200 metres from its endpoint, Bose took the impromptu decision to cancel the planned public meeting and stage the sit-in demonstration instead.

"Former chief minister Jyoti Babu (Basu) always said that if the government wants there will be a riot, and if it doesn't want it there will be none," Bose told the gathering during the sit-in.

"The police were not directed properly to prevent clashes during Ram Navami but they stopped our peace rally on Monday," Bose added.

Monday's peace rally was decided in response to the clashes that took place in Howrah's Shibpur on March 30 over Ram Navami celebrations. According to the Left Front, the clashes were a ploy to polarise voters on religious grounds.

The rally started at Salkia crossing and was about to conclude at Pilkhana. Within minutes of the commencement of the rally, the police forces resisted them. They erected barricades to stop the rally of around 7,000 Left supporters from advancing.

Left Front supporters initially engaged in a heated exchange and broke the barricades to move forward. The police resorted to lathicharge, which angered the Left activists further.

Sources said that the CPM's state secretary Md Salim received minor injuries during the clash.

"Salim-da was heckled by police and he fell down. However, he gathered himself and along with hundreds of rallyists, broke past the barricade to march ahead," a Howrah CPM leader said.

Angry with the police "high-handedness", CPM supporters tried to break past the police cordon. When the police could not resist the onward march of the protesters, the CPM leader said that cops were seen using batons to break the windscreen of a vehicle that was part of the rally.

"The chief minister said that she received intelligence that something would happen on the occasion of Ram Navami. If that was indeed the case, she should have gathered more details on it. Secondly, she should have taken chronological steps (to avoid the skirmishes)," Bose said.

He pointed out that the Howrah police were using a drone to keep watch on the peace rally. "Why was there no drone in Shibpur on March 30 during the Ram Navami procession? Would it (a drone) not have helped the administration to identify the culprits?" Bose asked.