A three-tier security has been put in place in and around the prison with armed guards being posted as part of security.
While police have cordoned off the area restricting public movement, access control measures have been put in place for visitors to the prison.
Scores of pro-Tamil groups and leaders, including MDMK founder Vaiko had staged a fast and organised human chains among other forms of protest across the state even as Vellore prison authorities are gearing up for execution of Murugan, Perarivalan and Santhan, who are likely to move the court on Monday against the Presidential rejection of the clemency petitions.
Political leaders, including PMK founder S Ramadoss and Vaiko have already demanded intervention of Chief Minister Jayalalithaa to whom the trio had sent a petition.
DMK president and former Chief Minister M Karunanidhi, whose party is a key constituent of the Congress-led UPA at the Centre, had demanded intervention of Congress President Sonia Gandhi in this matter.
It was at her behest that the death sentence of another convict, Nalini, was commuted to life a few years back in the same case.
Meanwhile, TNCC President K V Thankgabalu slammed the protests demanding clemency, saying rules cannot be bent for individuals.