Police baton charged violent Trinamool Youth Congress supporters at Burdwan district's troubled Mongolkote area on Saturday, prompting party chief Mamata Banerjee's to announce a rally at the same spot Tuesday.
The Trinamool workers hurled stones and bricks at police and later set afire a police vehicle.
Trouble began after a Trinamool Youth Congress meeting when party supporters tried to move towards Dhanyarukhi village, where the government had clamped prohibitory orders banning the assembly of more than four people.
District police chief R Rajshekharan said when police were trying to persuade the Trinamool activists to peacefully disperse, some partymen hurled brickbats.
"Some policemen were injured," Rajshekharan said, adding when more such missiles were thrown, police baton charged the violent mob.
At least 20 people have been detained. A TV grab showed police beating up Trinamool activists, including some middle aged ones.
Banerjee, who is the railways minister, warned the state's Left Front government that such incidents will be held against it.
"I will take up the matter at the right place," Banerjee told a Bengali news television channel from Delhi when asked whether she will apprise the central government of the Mongolkote incident.
Taking umbrage at the police action, Banerjee said: "It was a peaceful meeting. Why did the police behave in such a way? The CPI-M (Left Front major Communist Party of India - Marxist) does not know what harm it is doing to itself".
"I will go to the spot myself and hold a meeting. Let me see who stops me."
The area has seen trouble since CPI-M district committee member Falguni Mukherjee was shot dead from point blank range June 16.
The CPI-M alleged the attackers had links with the Trinamool Congress, but the opposition party has maintained that the killing was a result of a factional feud in the ruling party.