Argentina's President Cristina Fernandez de Kirchner inspects Chinese honour guards during a welcoming ceremony hosted by China's President Xi Jinping in the Great Hall of the People in Beijing, February 4, 2015. [Photo/Agencies]

The latest controversy comes as Fernandez struggles to distance herself from the mysterious death of prosecutor Alberto Nisman, who was found dead in his bathroom Jan 18, hours before he was to elaborate on allegations that Fernandez helped shield Iranians connected to the 1994 bombing of a Jewish community center that killed 85.

Fernandez has vehemently denied the accusations, saying Argentina had nothing to gain from such a deal. She has suggested that rogue elements in the intelligence services ordered Nisman's hit, but has not elaborated.

Earlier this week, just as her visit to China was getting underway, investigators looking into Nisman's death said they had found an arrest warrant for Fernandez that Nisman had written up. While he never presented it, the revelations brought Fernandez back to the center of the case.

On Wednesday, relatives of victims of the bombing marched with family members of the victims of Argentina's military dictatorship and other national tragedies to demand an end to impunity and the truth about what happened to Nisman.

Hundreds of demonstrators gathered in front of Congress in Buenos Aires with the march ending in the famed Plaza de Mayo.

"The demand for truth and justice that relatives of the AMIA (Jewish center) victims are making is the same as what we want for the 30,000 people who disappeared" during the dictatorship, said Nora Cortinas, who co-founded the Mothers of the Plaza de Mayo human rights group.