The Supreme Court on Tuesday reserved its judgment in the Rajiv Gandhi assassination case.
The convicts in the case had sought to commute the death penalty to life sentence due to delay in deciding their mercy plea.
The Centre has opposed the plea by arguing that the convicts did not go through torture, agony and dehumanising experience during pendency of the mercy pleas.
The Centre further told the Supreme Court that it is not a fit case for commuting death sentence.
Rajiv Gandhi was killed by a suicide bomber at an election rally in Sriperumbedur on May 21, 1991. Fourteen other people also lost their lives in that blast.
In 1999, the three convicts - Santhan, Murugan and Perarivalan - were sentenced to death by the Supreme Court for being part of the group that conspired to kill Gandhi.
Their mercy petition was sent to the President of India, the last stage in the process of appeals, in 2000 and was rejected 11 years later. Their hanging was stayed in 2011 on the orders of the Madras High Court.