In a letter to Union Home Minister Shivraj Patil [Images], CPM Politburo member Brinda Karat claimed that these outfits were indulging in "terrorist activities" and thus "seriously" undermining national security.

"The severest action be taken against the Bajrang Dal and VHP by applying the necessary procedures to check their terrorist activities," Karat said, and demanded "the outfits be put under the watch-list of outfits indulging in terrorist activities."

The CPM leader claimed that the recent incidents in Orissa have highlighted the use of violence by these outfits against Christians, including the use of weapons and inflammatory materials to burn houses and churches.

"In Bhubhaneswar, it was reported that the son of a Bharatiya Janata Party leader and his accomplice, associated with one of these organisations, were arrested when the bomb they were making exploded.

"Recently in Kanpur, two Bajrang Dal activists were killed while making bombs... In addition their leaders are making the most rabidly communal speeches," Karat said, adding that there were reports of attempts being made to spread violence in Madhya Pradesh [Images] and Rajasthan by these outfits.

In her letter, she also pointed to the revelation by the anti-terror squad of the Mumbai police that these outfits have a "carefully prepared plan" to create communal disturbance by exploding bombs.