The three men on death row for their involvement in the assassination of former prime minister Rajiv Gandhi on Monday moved the Madras High Court to stay their September 9 hanging, even as the DMK and some other parties called for commutation of their death sentence.

Urging the centre to save the three lives, DMK chief M. Karunanidhi said in a statement: "Had young leader Rajiv Gandhi been alive today, that noble man would have definitely come forward to save the lives of Santhan, Perarivalan and Murugan, responding to the voice of true Tamils and in accordance with the golden saying of Anna, forget and forgive."

MDMK general secretary Vaiko and advocate N. Chandrasekaran also filed the petition on behalf of the condemned prisoners - Murugan alias Sriharan, T. Suthendraraja alias Santhan and A.G. Perarivalan alias Arivu. The petition will be heard by Justice Paul Vasanthkumar on Tuesday.

"Vaiko has filed the petition on behalf of Perarivalan. Vaiko is the counsel on record. Senior advocate Ram Jethmalani will appear for Perarivalan. The case is expected to come up for hearning on Tuesday morning," MDMK legal wing secretary G. Devadoss said.

Chief Minister J. Jayalalithaa, has however, told the state assembly that she had no power to grant pardon to the convicted.

Jayalalithaa, while speaking in the assembly, quoting a union home ministry directive said that when a petition for grant of pardon in death sentences has earlier been rejected by the president, it would not be open for the state to invoke Article 161 to commute the death sentence.

Striking back at Karunanidhi's request, she pointed out that in 2000 Karunanidhi had recommended to the governor to reject the mercy plea of the three and commutation of death sentence to Nalini to life.

However, DMDK leader Vijayakanth, an ally of Jayalalithaa, in a statement demanded 'cancellation' of the death sentence of the three.

In New Delhi, Congress spokesperson Abhishek Singhvi declined to comment on the issue.

Back in Chennai, the fast by three female advocates Angayarkanni, Vadivambigai and Sujatha in support of the three convicted men continued for the fourth day on Monday.

There was also a self-immolation bid by a city auto driver.

The police arrested about 100 students of a law college when they tried to take a procession to Raj Bhavan demanding the governor's intervention to save the convicts.

Students in Madurai and Coimbatore also held demonstrations, reports said. Two students of the Government Law College in Madurai climbed to the roof top of a building and threatened to jump but were later persuaded by police to climb down.

On August 11, President Pratibha Patil rejected the mercy petitions of the trio, linked to the LTTE and sentenced to death for involvement in the 1991 assassination.

A woman suicide bomber blew herself up, killing Gandhi, prime minister of India from 1984 to 1989, at an election rally in Sriperumbudur near Chennai May 21, 1991.

14 others also lost their lives in the blast.

In 1998, all the 26 accused in the case - including the three - were sentenced to death by a special trial court for Gandhi's killing.

In 1999, the Supreme Court confirmed the death sentences of four: Murugan, Santhan and Perarivalan and Nalini, an Indian woman who had assisted the killer squad. The capital punishment of the others was reduced to varying terms of imprisonment.

The death sentence of Nalini, who became a mother in prison, was commuted to life imprisonment after her mercy petition was accepted. The petition had the recommendation of Sonia Gandhi, Rajiv Gandhi's widow.

Murugan, Santhan and Perarivalan and the others were charged with criminal conspiracy that led to the killing.

Soon after the confirmation of their sentence, they made a mercy plea to the Indian president, which was rejected on August 11.