On each passing anniversary of the deadly 1994 attack against Argentina's largest Jewish community centre, Diana Malamud says she endures a brutal "Groundhog Day".

In her version of the nightmare that traps her in the same day over and over, presidents repeat the same pledges to seek justice for the car bombing at the centre that killed 85 people, including Malamud's husband, Andrés, wounded 300 others and profoundly unsettled Jewish communities across the continent.

No has ever been convicted for involvement in the bombing, considered among the deadliest antisemitic attacks anywhere since World War II.

On the 30th anniversary of the attack, President Javier Milei became Argentina's 11th leader to vow renewed efforts to bring perpetrators to justice.

His combative anti-Iran rhetoric, pro-Israel foreign policy and radical state reforms have stirred cautious optimism about his commitment to breaking the time loop.

Argentina President Javier Milei attends a commemoration event ahead of the anniversary of 1994 bombing attack. – Reuters

Milei has signed legislation to make July 18 a national holiday.

But many remain unconvinced after three decades of an investigation marred by corruption, obfuscation and intrigue.

"The years go by, but nothing happens," said Malamud, 64, a member of Active Memory, a group of victims' families that has pushed for accountability.

"On these anniversaries, the government has very important announcements that never serve any purpose."

A memorial siren wailed at the community centre, known by its Spanish acronym AMIA, on Thursday at 9.53am, the exact minute the attack occurred 30 years ago, commencing the day of stirring speeches and solemn vigils.

"It's unbelievable that 30 years have passed since that cold morning of 18 July 1994, 30 years without a single person answering for this attack," the head of AMIA, Amos Linetzky, told the crowd of dignitaries at the memorial service, his voice rising with frustration.

People hold images of the victims of the 1994 bombing attack as they mark the 30th anniversary of the attack. – Reuters

Milei was in the audience to show support, raising a portrait of one of the 85 victims.

At a conference hosted by the World Jewish Congress the day before, he vigorously denounced Iran as "the dark hand" behind militant attacks from Argentina to Israel.

Argentine prosecutors have repeatedly blamed Iran for directing the attack and dispatching Lebanon's Hezbollah militant group to execute it – claims denied by Iran.

"There is no reasonable person who doubts that sectors of Iran's fanatical government are behind these atrocities," Milei said.

He equated the Hamas militant attack against Israel on October 7 with the AMIA bombing as well as an earlier 1992 attack on the Israeli Embassy in Buenos Aires.

Messages of solidarity poured in from around the world. Pope Francis expressed hope his compatriots would "not give up in the search for justice".

US Secretary of State Antony Blinken took the occasion to condemn "all manifestations of antisemitism" that he said have surged around the world in the wake of the Israel-Hamas war.

Israeli President Isaac Herzog sent "heartfelt thanks" to Milei for his commemoration efforts and "for standing in solidarity with the Israeli people as we continue to face the threat of terror and hatred".

Milei has been strikingly vocal in his defence of Israel since the October 7 attacks, promising to move Argentina's embassy to contested Jerusalem and supporting the Israeli military's devastating campaign in Gaza – in contrast to neighbouring Latin American countries that have pulled their envoys from Tel Aviv and severed ties with Israel.

Argentine President Javier Milei prays at the Western Wall in Jerusalem. – AP file

Milei has also professed a profound spiritual connection to Judaism and forged close ties with the Jewish community in Argentina, the biggest in South America.

Although Milei hasn't yet converted to Judaism, he studies Torah and regularly consults with a personal rabbi who he has appointed as the country's ambassador to Israel.

The dramatic foreign policy shift – after previous Argentine governments attempted to collaborate with Iran to investigate the bombing – has delighted Israel and Jewish advocacy groups.

"The thing that's different, finally, is that there's a new president in Argentina," said Ted Deutch, CEO of the American Jewish Committee and a former US congressman, praising the "shared values" that he said now unite Argentina, the US and Israel in new ways.

"The president of the country speaks with clarity about this issue in a way that resonates."

In the past week, Milei designated Hamas as a terrorist organisation, announced a revamp of the intelligence services and vowed to introduce legislation that would allow for the trial of suspects in absentia.

Despite Interpol notices for their arrests, several Lebanese and Iranian citizens accused of involvement in the attack – including Iran's interior minister – remain at large.

In a ruling last month, the Inter-American Court of Human Rights held the Argentine state responsible for its failure to prevent the attack and accused it of deliberately obstructing justice.

It ordered the government to continue its investigations into alleged attempts by officials to cover up Iran's involvement in the attack.

The names of bombing victims and the Spanish phrase "Memory and Justice" cover a wall at the bombing site. – AP

Members of Active Memory have celebrated the order by the legal body, whose jurisdiction Argentina acknowledges.

But they said they have little faith in their government to close the case.

"The important thing is to move from gestures and words into concrete action," said Active Memory member Enrique Greenberg.

As usual, the group held its own vigil in downtown Buenos Aires at the same time as the AMIA ceremony – the short distance between the events a product of the bitter divisions that the elusive quest for justice has spawned within Argentina's Jewish community.

There were no government officials at the Active Memory service, where Malamud delivered a tribute similar to the many she has given before.

Nonetheless, she found herself moved to tears.

"As has happened to me so many times, in this same square," she said, "the face of my husband Andrés comes to me like a wink".