PARIS — A Belgian husband and wife of Iranian origin have been charged with plotting to bomb a rally held last week in France by an exiled Iranian opposition group, the Belgian authorities said on Monday.
The suspects, identified only as Amir S., 38, and Nasimeh N., 33, were arrested on Saturday in Sint-Pieters-Woluwe, a borough of Brussels, according to a statement by Belgium’s Federal Public Prosecutor’s Office and its Federal Intelligence and Security Agency.
The statement said the couple were suspected of planning to bomb a gathering on Saturday of the Mujahedeen Khalq, or People’s Mujahedeen, a group that advocates the overthrow of the Iranian leadership. The group, known as the M.E.K., had long been on the State Department’s list of foreign terrorist organizations but was removed in 2012 after intense lobbying efforts.
About 25,000 people attended the rally, called “Free Iran 2018 — The Alternative,” at a convention center in Villepinte, a northeastern suburb of Paris.
The M.E.K., which is sometimes described as a fringe, cultlike organization, is scorned in Iran for its alliance with the toppled Iraqi leader Saddam Hussein. But several prominent American figures have touted it as a viable alternative to the Iranian leadership, including close allies of President Trump, like John R. Bolton, his national security adviser.
Rudolph W. Giuliani, the president’s personal lawyer, and Newt Gingrich, a former House speaker, both spoke at the rally, with Mr. Gingrich calling it “impressive and emotionally powerful” on Twitter.
The couple suspected of plotting the attack were arrested on Saturday in their Mercedes, the Belgian authorities said in their statement. In the car, the police found a “small toiletry bag” containing about 500 grams, or a little over a pound, of triacetone triperoxide, a homemade explosive known as TATP, as well as an “ignition mechanism.”
The couple have been charged with attempted terrorist murder and the preparation of a terrorist offense, the statement said. It added that the police had raided five houses in and around the Belgian cities of Brussels, Antwerp, Mons and Leuze-en-Hainaut in connection with the case, but that they could not disclose the results of the searches.
“The provisional state of the investigation shows that there was at no time a direct threat to Belgium,” the statement said, noting that the arrests had been made possible by cooperation between the Belgian, French and German authorities.
Three people were arrested in France on Saturday in connection with the foiled plot, but only one was still in custody on Monday evening, according to a French judicial official, who spoke on the condition of anonymity in line with official policy.
The official did not identify those who had been arrested, saying only that they had been taken into custody to “clarify” potential ties with the couple arrested in Belgium and that two of them had been released for lack of incriminating evidence. The statement by the Belgian authorities identified the suspect still in French custody as Merhad A., 54, a suspected accomplice of the couple.
A 46-year-old Iranian diplomat working at the Austrian Embassy in Vienna was also arrested in Germany as a contact for the couple. He was identified as Assadollah A.
The National Council of Resistance of Iran, a Paris-based group that organized the rally and is dominated by the M.E.K., blamed the Iranian government for the plot.
“The clerical regime’s terrorists in Belgium, with the assistance of the regime’s diplomats, had plotted this attack,” said Shahin Gobadi, a spokesman for the group, in a statement.
Javad Zarif, the Iranian foreign minister, countered on Twitter that Iran “unequivocally condemns all violence & terror anywhere, and is ready to work with all concerned to uncover what is a sinister false flag ploy.”
The M.E.K. was founded in Iran as a dissident group that targeted the regime of the shah and then the religious clerics who overthrew him with terrorist attacks in the 1970s. It also targeted Americans and was on the State Department’s list of terrorist organizations from 1997 to 2012. The group is made mostly of Iranian exiles living in the United States or in Europe.