Iran has offered to aid the investigation into the deadly bombing of a Buenos Aires Jewish centre, 17 years after the attack.
Argentinian prosecutors have long implicated Iran in the blast at the Jewish-Argentine Mutual Association (AMIA) centre, which destroyed the seven-floor building, leaving 85 dead and 300 injured.
Six influential Iranians, including former Iranian President Ali Rafsanjani and Defence Minister Ahmad Vahidi, were placed on Interpol's most wanted list in 2007 for suspected involvement in the bombing on July 18, 1994.
Vahidi has been accused by Argentinian investigators of being the mastermind behind the atrocity and collaborating with Hizbollah.
But no arrests have been made and the investigation has been beset by accusations of witness bribery, irregularities and allegations of a high-level cover-up.
In a statement this week, the Iranian Foreign Ministry said it would co-operate with the investigation so as to "shed all possible light" on what happened. However, it continued to deny being behind the attack.
The Argentinian Foreign Minister, Hector Timerman, said that if the help materialised it would represent an "unprecedented and very positive advance from the Iranian authorities".
However the offer was also viewed with suspicion, with Alberto Nisman, a prosecutor for the case who has blamed Iran for it, noting that "declarations empty of real content" were not enough and Iran needed to bring all the suspects to justice.
To mark the anniversary of the bomb, the worst terrorist attack in the South American nation's history, Argentinian national footballers including Leo Messi and Carlos Tevez joined a call for a "Strike Against Forgetting" the AMIA victims.
President Cristina Fernandez de Kirchner and Mr Timerman also attended a memorial ceremony organised by AMIA, where a siren was sounded at the time of the attack.
The AMIA bomb followed the deaths of 29 people in a blast at the Israeli embassy in Buenos Aires two years earlier.
Investigators also linked Iran to that attack.