New Delhi: Armed with fresh revelations in the Ishrat Jahan encounter case, the Bharatiya Janata Party (BJP) on Tuesday accused the Congress of playing with national security in trying to frame then Gujarat chief minister Narendra Modi and demanded an unconditional apology from the grand old party for supporting terrorists.

"It is really astonishing to see that political leaders can stoop down to that level. This is the kind of politics the Congress Party has played with the nation. The Congress must come clean and should render an unconditional apology. The stigma of supporting such activities will continue to haunt the Congress Party even in future also," Union Parliamentary Affairs Minister M. Venkaiah Naidu told the media.

Read: Made only 'editorial' changes in Ishrat files: Chidambaram

"The Congress Party must come clean on the Ishrat Jahan episode. It is a serious issue that a party can stoop down to that dirty level to change the affidavit and try to implicate political leaders by siding with Pakistan's sponsored terrorists. The entire UPA Government has to take the responsibility. It is not P. Chidambaram alone," he added.

Naidu further stated that Chidambaram would not have done it for himself, but for his party.

The senior BJP leader added that the then UPA regime took this decision not only to harass Narendra Modi but also in the process making him vulnerable to the terrorist attacks.

"Chidambaram earlier has gone on records that as facts have come to his notice he had changed the affidavit. He suppressed the facts that he signed the original affidavit also even after (then home secretary) G.K. Pillai made it public," said Naidu.

"The Congress was silent and Chidambaram also was trying to justify the change of the affidavit. But now, the truth is out. One of the channels has come out with the truth and the truth is not being contested," he added.

Based on RTI disclosures, a leading English news channel claimed on Monday that Chidambaram had seen and signed the first affidavit, a fact that he has denied so far.

Chidambaram said that he would not like to comment without pursuing the files and the noting.

New developments unfolded in the Ishrat Jahan case with the 51-page file of the Ministry of Home Affairs (MHA) recording that Chidambaram had signed the original affidavit describing Ishrat as part of a Lashkar module.

Media reports revealed that Chidambaram had in fact signed the first affidavit, which declared Ishrat and three others as terrorists, but gave all four a clean chit a month later as serious amendments were made in the second affidavit also signed by him.

The first affidavit in the encounter case stated that Ishrat was a LeT operative, who was part of a plot to assassinate the then Gujarat chief minister Narendra Modi.

Chidambaram had initially claimed that the first affidavit declaring Ishrat and three others as terrorists was filed in the court without his approval, adding that he had made some editorial changes to avoid misinterpretation when the matter was brought to his notice.

Chidambaram, however, completely altered his stance in the second affidavit, saying that intelligence inputs on Ishrat and the three others did not constitute conclusive proof and favoured a Central Bureau of Investigation (CBI) probe in the encounter.