Several activists were on Sunday injured in a clash between a right wing Hindu outfit and CPI(M) at the Left party's headquarters here in the wake of a flare-up in the violence involving the two sides in Kerala's Kannur district.

RSS men clashed with CPI(M) workers and started pelting stones at the party office where a central committee meeting of the Left party was going on, police sources said.

CPI(M) workers retaliated and in the ensuing clash activists of both sides were injured. Among the CPI(M) activists injured are four central committee members, Joginder Sharma, Hari Singh Kang, Pushpender Grewal and Sriniwas Rao.

The Rapid Action Force was immediately deployed in the area to contain the situation after police lobbed teargas shells to disperse the activists.

Windows of the AKG Bhavan in Gole Market in central Delhi were broken and 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.

The CPI(M) has lodged an FIR with Delhi police which has named Delhi Assembly opposition leader Jagdish Mukhi and Delhi mayor Aarti Mehra among others.

While CPI(M) claimed that about 16 of their activists were injured, the RSS said 12 of their workers were hurt. Senior police officials said 14 people were detained in connection with the incident.

Reacting to the attack on the CPI(M) headquarters, party Politburo member Sitaram Yechury alleged, "The RSS was trying to spread the culture of terror in the national capital as they were doing in Kerala [Images]."

"They were protesting against what has happened in Kerala but the fact is that we have lost the largest number of cadres in the attacks by the RSS in the southern state," Yechrury told reporters in New Delhi.

Blaming the police for "not taking necessary steps to avoid the incident", he alleged, "everyone including police knew that there will be a protest march here today but adequate arrangements were not made".

Lashing out at the RSS, he said, "They are the people who had stooped to the level of assassinating the Mahatma. What else can you expect from them. This is the fascist character."

In his reaction, CPI MP D Raja said violence and intolerance can't be allowed in a democracy and accused the BJP leadership of settling scores in a violent way.

Raja said the BJP leadership should take responsibility for today's violence in Delhi and all democratic forces should condemn that strongly.

BJP deputy leader in the Lok Sabha V K Malhotra said his party will raise the issue of political violence in Kerala's Kannur district in Parliament on Monday.

"We condemn the murder culture of the CPI(M). They have done it in Nandigram [Images] and have been doing it for several years in Kerala," he said.

Malhotra claimed that BJP and RSS workers, demonstrating outside CPI(M) headquarters here, were attacked and around 15 activists were injured when stones were pelted on them from inside the Marxist party's office.

Members of Bharatiya Janata Yuva [Images] Morcha (BJYM) had staged a demonstration in front of the CPI(M) headquarters during which police used water canons to disperse the agitating crowd.

The Kannur district of Kerala is witnessing clashes between the CPI-M and BJP-RSS workers and seven lives had been lost since Wednesday.