New Delhi  - Indian leaders Thursday paid tribute to former prime minister Rajiv Gandhi, who was assassinated on May 21, 1991, by a Sri Lankan Tamil Tiger suicide bomber during an election rally in the southern state of Tamil Nadu.

The Sri Lanka government announced Monday that it had defeated the separatist Liberation Tigers of Tamil Eelam (LTTE) and that its leader Velupillai Prabhakaran had been killed.

Prabhakaran was found guilty in the Rajiv Gandhi assassination case and was sentenced to death in absentia.

He is believed to have hatched the plot to assassinate Gandhi along with his intelligence chief Pottu Amman.

India is believed to have sought Prabhakaran's death certificate so that the case could now be closed, Times Now television channel reported.

The rest of those found guilty have either died or are in jail.

The request was reportedly made by India's National Security Advisor MK Narayanan and Foreign Secretary Shivshankar Menon, who are currently in Sri Lanka for talks.

Indian Prime Minister Manmohan Singh sent the two officials to Sri Lanka to help seek a political solution to the Tamil issue and offer help in the effort to rehabilitate displaced Tamils.

The plight of Sri Lankan Tamils is an emotive issue in India's southern Tamil Nadu state, which has a large population of ethnic Tamils.

Sonia Gandhi, widow of Rajiv Gandhi and president of India's Congress Party which leads the alliance which won the recent general elections, paid floral tributes to her husband at his memorial Veer Bhumi (land of the brave) in the Indian capital.

She was accompanied by her son Rahul Gandhi, who is a general secretary of the party, daughter Priyanka and several senior party leaders.

An all-religion prayer meeting was organized at Veer Bhumi.

The Congress Party-led United Progressive Alliance emerged the largest coalition in Parliament in the recent general elections and a new government headed by Singh is expected to be sworn in Friday.(dpa)