An Argentine judge on Thursday indicted a former president for allegedly trying to cover up Iran's purported role in a deadly 1994 terrorist attack on a Jewish community center in Buenos Aires.

Claudio Bonadio also urged the Senate to remove Cristina Fernandez's congressional immunity from arrest so she can be placed in pre-trial detention while the investigation proceeds.

The judge made the request on the grounds Fernandez could obstruct the probe, which stems from explosive allegations in January 2015 by special prosecutor Alberto Nisman, who died almost three years ago.

As part of the same probe, Bonadio also ordered the preventative detention of Carlos Zannini, a former legal and technical secretary during Fernandez's 2007-2015 administration; and labor leader Luis D'Elia, both of whom have already been taken into custody.

The judge furthermore ordered that former Foreign Minister Hector Timerman be held in preventative detention, although he was granted house arrest due to his poor health.

Nisman said a 2013 deal between Fernandez's administration and Iran to jointly investigate the deadly 1994 suicide bombing at the offices of the AMIA organization, an attack that left 85 dead, was in fact aimed at providing impunity for top Iranian officials.

The deal involved a quid pro quo whereby the two nations were to boost bilateral trade and Iran was to supply oil to energy-hungry Argentina, Nisman alleged.

Nisman was found dead in his apartment of a gunshot wound to the head on Jan. 18, 2015, just days after leveling the bombshell allegations, a case that is currently classified as a "suspicious death."

The Argentine courts dismissed Nisman's charges against Fernandez shortly after his death, although the case was reopened late last year and subsequently merged with another (also overseen by Bonadio) that accused the ex-president of treason in connection with that same Iran deal.

The re-opening of the AMIA cover-up case came a year after current President Mauricio Macri took office as head of state, ending 12 years of center-left rule by Fernandez and her late husband Nestor Kirchner.

Argentina's Jewish community blames Iran and Lebanese Shiite militia group Hezbollah for planning the bombing, which followed a 1992 terrorist attack on Israel's embassy in Buenos Aires that left 29 people dead and more than 200 wounded.

Prosecutors have yet to secure a single conviction in the AMIA case.

Fernandez, who has asserted that the charges against her are politically motivated, said in a court filing that the only purpose of the memorandum of understanding with Iran was to achieve an advance in the AMIA case.

Besides being investigated in the terrorist cover-up case, Fernandez faces indictments for allegedly overseeing irregularities in the sale of dollar futures contracts by the Central Bank at below-market rates during her tenure as president and alleged conspiracy in the awarding of public-works contracts.

But she is shielded from arrest or search warrants by virtue of having won a Senate seat in midterm elections on Oct. 22.

That immunity could be stripped away, but it would require a two-thirds vote in the Senate.