Agartala, Feb 15 (IANS): Ruling CPI-M's leaders and members on Monday organised protest rallies and demonstrations across Tripura to protest over an attack on the party headquarters in New Delhi.

Many protest rallies and demonstrations were organised in different parts of Tripura to protest the attack on Sunday on the headquarters of the Communist Party of India-Marxist (CPI-M) -- A.K. Gopalan Bhavan -- in New Delhi allegedly by "Hindu rightist forces".

"Some spontaneous protest rallies and demonstrations were held yesterday (Sunday) itself. We urge upon the authorities to take appropriate steps to punish the culprits for their act of cowardice," CPI-M leader Tapas Datta said.

"The heinous attack was done following the CPI-M's support to the Jawaharlal Nehru University students who are protesting against the arrest of union leaders and supporters," Datta said.

A group of youths, identifying themselves as "Aam Aadmi Sena", on Sunday tried to vandalise the CPI-M headquarters.

The three youths sprayed black ink on the wall of the office building and sign board.

They tried to write slogans like "Pakistan Zindabad" on the office board. One of them was caught and handed over to police.

Delhi Police have stepped up security around the CPI-M office in New Delhi after the party received telephone calls threatening its general secretary Sitaram Yechury for supporting JNU students slapped with sedition charges.