LILLE, France/PARIS (Reuters) - French police raided a Shi’ite Muslim faith center and arrested three of its leaders for illegal weapons possession in pre-dawn swoops on Tuesday that government officials said were prompted by suspicion of links to terrorist organizations.

France, home to Europe’s largest Muslim community, remains on maximum alert after attacks in recent years in which Islamist militants and people inspired by radical groups such as Islamic State have killed close to 250 people.

Paris also accused Tehran on Tuesday of plotting to bomb an opposition rally in Paris earlier this year.

Some 200 police officers including elite troopers from Paris took part in raids that began under darkness at the Centre Zahra France and homes of a dozen of its members, in Grande Synthe near the northern port town of Dunkirk.

“This is a counter-terrorism operation,” the local prefect’s office said a statement.

“The activities of Centre Zahra France are under particularly close watch given its leaders’ clear support for several terrorist organizations and movements espousing ideas contrary to (French) republican values.”

Interior Minister Gerard Collomb said three people were put in custody after the discovery of illegal arms, and that a prayer room was being shut.

The raids coincided with an announcement that France had also seized assets belonging to Iran’s intelligence services and two Iranian nationals over a June plot to attack an exiled Iranian opposition group’s rally outside Paris.

Two sources said there was no direct link between the raids and the Iranian intelligence asset freezes.

However, a French diplomatic source said that while the two incidents were not linked, the raid on the Zahra aimed to show that Paris would also not tolerate radical Shi’ite groups.

It’s not linked ... but we will not accept any form of terrorism or incitement of terrorism on our national territory,” the source said.

“The Zahra center is not an official Iranian entity, but it is a center of influence with typical Shi’ite messages and which propagates radical messages including by bringing closer together movements that we deem unacceptable ... it is a center of Shi’ite interference.”

Assets of the Centre Zahra France were frozen too, along with financial assets held under other names, on orders issued by France’s interior and finance ministry, a notice published in the official government journal of legal acts said.

The center’s website says it has some 8,000 “followers” on social network sites and its goal is to spread the message of Islam via film, radio, writings and conferences. It also offers a contact point on social, family and religious matters.

France, which is historically a predominantly Roman Catholic country, is officially secular, with separation by law between matters of state and religion for over a century. It is home to five million or more Muslims out of a population of 67 million.