The Supreme Court on Tuesday asked the Union home secretary to file an affidavit, whether the Centre is committed to adhere to the assurance given by the then deputy Prime Minister L.K. Advani to Portugal authorities, to not incarcerate gangster Abu Salem for more than 25 years while seeking his extradition.

A bench comprising Justices Sanjay Kishan Kaul and M.M. Sundresh said the Centre has to make its stand clear on the issue.

The bench emphasized that not abiding by the assurance made to the Portugal authorities, could have wider ramifications and it may create problems while seeking extradition of fugitives from other countries. The top court said it is not happy with the CBI's reply in the matter and sought a response from the home secretary in three weeks.

The CBI, in its affidavit, has told the top court that an Indian court is not bound by the assurance given in 2002 by the then deputy prime minister to the courts in Portugal that gangster Abu Salem would not be imprisoned beyond 25 years after his extradition to India.

Advocate Rishi Malhotra, representing Salem, argued before the bench that as per the principle of reciprocity in Portugal the courts cannot award a sentence for more than 25 years. He added that based on the principle of reciprocity, the Government of India had given a solemn sovereign assurance to the Portugal courts that in case Salem is permitted to be extradited back to India, he will not be given punishment for more than 25 years.

The CBI's affidavit said: "The solemn sovereign assurance given by the then Deputy Prime Minister of India cannot be construed as a guarantee/ undertaking to assure that no court in India would award the punishment provided by Indian laws in force to the accused Abu Salem."

The CBI said that Salem's argument that imprisonment term cannot extend 25 years as per the assurance given is legally unsustainable. "This court while deciding criminal appeal...filed by Abu Salem Abdul Qayyum Ansari has held that both India and Portugal are two sovereign unequivocal terms, the verdict by the constitutional court of Portugal is not binding on this court but only has persuasive value," added the affidavit.

On February 2, the top court asked the Centre and the prosecuting agency to make their stand clear on the applicability of the solemn sovereign assurance given by the then deputy Prime Minister to Portugal.

Salem had cited these assurances given by the Indian authorities before the courts in Portugal in 2002 and 2005 that he will not get death penalty or a jail term beyond 25 years. He was brought to India in 2005 and sentenced to life imprisonment for his role in the 1993 Mumbai blasts.