The diplomat, who works at the Austrian embassy in Vienna, was detained in Germany. He is allegedly the contact of a married Belgian couple of Iranian origin, who were arrested in Brussels with 500 grams of the chemical explosive TATP and a detonation device.

The Belgian federal prosecutor said that the couple “are suspected of having attempted to carry out a bomb attack” on Saturday in the Paris suburb of Villepinte. The National Council of Resistance of Iran (NCRI) was holding their annual Grand Gathering. “Free Iran”, to support regime change there at the time.

In France, three other people were arrested in connection with the bomb plot. One was detained on Saturday afternoon near the event, and the other two who were arrested in Senlis, north of Paris. According to a French judicial source, they were released due to a lack of evidence against them.

Tehran regularly criticizes the NCRI in state media, and has long called for a crackdown on the group in Paris, Riyadh, and Washington.

NCRI spokesman Shahin Gobadi said, “A plot by the religious dictatorship ruling Iran to carry out a terrorist attack against the grand gathering of the Iranian resistance in Villepinte was foiled.”

Belgian authorities also conducted five raids in different parts of the country following the arrests, but did not comment on whether anything was found.

Belgian Prime Minister Charles Michel took to Twitter to thank the police and intelligence officers for their work. “Once more the good cooperation between countries has borne fruit,” Michel wrote.

Tens of thousands of people attended Saturday’s rally in Paris. They waved the red, green and white flag of the NCRI, cheered its leader Maryam Rajavi and called for regime change in Iran.

Former New York mayor and Trump legal advisor Rudy Giuliani, and the former House of Representatives Speaker Newt Gingrich, and other leading politicians from the US, Europe and the Middle East all attended the event.

Giulani addressed the rally, saying “Freedom is right around the corner.” He also called for a boycott of companies “that continually do business with this regime.”

Salman Al-Ansari, head of the Saudi American Public Relation Affairs Committee, affirmed to the attendees of the rally that the Iranian opposition was sending a strong message of “hope and peace” against a regime of “conspiracies and violations.” He added, “The Iranian regime is a system based on conspiracies and violations against the safe and secure countries and peoples such as the Yemeni, Syrian, Lebanese or Iraqi people.” The efforts of the Iranian opposition would ensure that “the true face of Iran returned to what it used to be in the past — the cradle of great human civilizations,” he continued, “Throughout your 53 years of heroic history of sacrifice … the great Iranian people have been subject to great and unprecedented oppression and injustice. Today is a victory for civilized and knowledgeable Iran. The Iran of civilization and humanity, Iran of science and culture, Iran of tolerance and brotherhood, not the Iran of Khomeini and Khamenei and Soleimani and Rouhani.”

In Iran, protests over polluted water in Abadan continued on Monday, after 11 people were injured in protests on Saturday.