The Brussels Great Marked Square in Belgium. Photo: Creative Commons via Wikimedia Commons.

Belgium has issued a European arrest warrant for a man of Iranian origin that is being held in France suspected of being involved in an alleged plot to bomb an Iranian opposition rally on the outskirts of Paris, a French judicial source said.

Belgium authorities are already investigating two Belgians of Iranian origin whom they arrested on Saturday, on the day of the National Council of Resistance of Iran (NCRI) meeting, with 500 grams of the homemade explosive TATP and a detonation device found in their car.

The exiled Iranian opposition group’s meeting was attended by Donald Trump’s lawyer Rudy Giuliani.

“A European arrest warrant has been issued (for the suspect held in Paris) by the Belgian authorities,” the French judicial source said on Wednesday.

An Austria-based Iranian diplomat is also being questioned in Germany over the incident.

Iran has said it had nothing to do with the plot and was willing to help with the investigation. It has accused the People’s Mujahideen, the main component of the NCRI, of being responsible.

French officials have declined to comment on the case saying the nature of the incident is unclear and very sensitive.

After the withdrawal of the United States from the 2015 Iran nuclear deal, its European signatories Britain, France and Germany have vowed to save the agreement despite the US pushing them to pullout.

Any sign Iranian authorities were behind the plot in France could make it politically complicated for leaders, especially President Emmanuel Macron, to continue to back the deal.

The Austrian Foreign Ministry said on Tuesday it was stripping the diplomatic status of 46-year-old Iranian diplomat, Assadollah A, who was arrested in Germany, suspected of having been in contact with the two arrested in Belgium.

Iran’s foreign ministry has rejected as baseless the allegations against the diplomat.