The protest turned violent as scores of Hindu Mahasabha activists clashed with CPM workers and started pelting stones at the party office where a CPI(M) Central Committee was meeting, police sources said.
CPI(M) workers retaliated and in the ensuing clash ten of the Left party activists were injured. One of them is said to be in a serious condition.
Rapid Action Force was immediately deployed in the area. Police lobbed teargas shells to disperse the mob. Windows of the AKG Bhawan were broken and the ground floor of the building which houses the office of the party organ People's Democracy suffered extensive damage.
Window panes of a number of cars including that of CPI(M) General Secretary Prakash Karat and Politburo member Sitaram Yechury were broken during the violence. The party suspended its Central Committee meeting and was holding an urgent poiltburo meeting to discuss the situation.
Several activists of the Hindu Mahasabha were detained in connection with the incident, the sources said.