The mother of a man convicted for his role in the assassination of former Prime Minister Rajiv Gandhi has started a public petition campaign in Sri Lanka seeking the release of her son from a jail in Tamil Nadu.

Vetrivel Somini, mother of Murugan who has been in jail after his conviction in the Rajiv Gandhi assassination case,said she is aiming to get one million signatures for the petition to seek the release of her son and six others.

Murugan, married Nalini Sriharan who had accompanied the bomber Dhanu to Sriperambudur. Nalini is also serving a life sentence has a daughter. The duo have a daughter, Meghara.

Somini, who lives in Sri Lanka's Kilinochchi, the former administrative capital of the Liberation Tigers of Tamil Eelam (LTTE), said she hopes to submit the petition to Prime Minister Narendra Modi. Murugan, a resident of Pallai in Kilinochchi, has been in jail for the last 25 years.

Somini said there were examples when world leaders had pardoned convicts accused of grave crimes and so she expects her son to be given clemency.

The Liberation Tigers of Tamil Eelam (LTTE) carried out Rajiv's assassination on May 21, 1991 in Sriperumbudur.

The LTTE had killed Rajiv to exact revenge for his decision to send the Indian Army to Sri Lanka under the 1987 Indo-Lanka Peace Accord.

Dampening hopes of release for the killers of Rajiv, India's Supreme Court in December had ruled that the Centre has "primacy" over states' right to grant remission and referred the issue of clemency for the assassins to a three-judge bench.