BRUSSELS — The Belgian government has decided to terminate the long-term lease of the country’s largest and oldest mosque to the Saudi royal family, as part of what officials say is an effort to combat radicalization.

The move caps a long-running discussion about what to do about the Grand Mosque of Brussels, a sprawling complex in the heart of the city where worshipers mix with bureaucrats and diplomats headed to the nearby glassy office buildings of the European Union. The mosque, administered by Saudi-backed imams, has been a target of Belgian security services for years. But after radicalized Belgians emerged as key players in terrorist attacks in France and Brussels in 2015 and 2016, policymakers felt new urgency to take action. 

Belgian King Baudouin signed over the mosque for 99 years, rent-free, to Saudi King Faisal in 1969 as a goodwill gesture, which also secured cheaper oil for the European nation. 

A parliamentary commission set up to make Belgium safer after the March 22, 2016, Brussels attacks recommended in October that the lease be broken.

The Belgian government said in a statement Friday that it is seeking “to put an end to foreign interference in the way Islam is taught in Belgium.”

“With this, we end Salafist, violent extremist influences,” Belgian Interior Minister Jan Jambon wrote on Twitter.

The Mecca-based Muslim World League, which runs the Grand Mosque and is largely but not exclusively supported by the Saudi government, will have a year to vacate.

Belgian leaders plan to hand management over to the Muslim Executive, the official government-backed umbrella group for Belgium’s Muslims, many of whose families emigrated in the 1960s from Morocco and Turkey.

The decision puts the government in the position of picking ideological winners and losers among strains of Islam.

Belgian security officials acknowledge they have never heard anything illegal preached at the mosque. And there is no any evidence that anyone connected to the attacks worshiped there. When Belgian authorities last year tried to deport the main imam, Abdelhadi Sewif, a judge struck the effort down, saying there was no evidence he threatened Belgian society. He was allowed to remain in the country, where he has lived for 13 years. 

The mosque’s leaders insist they preach an inclusive vision of Islam. But Belgian authorities contend that the imams encourage congregants to close themselves off from mainstream society.

Sewif, an Egyptian with ties to Cairo’s conservative powerhouse Al-Azhar University, does not speak French or Dutch, Belgium’s two main languages.

Lawmakers want the mosque “to be managed by Belgian Muslims, in a transparent manner, not by a foreign power,” said Gilles Vanden Burre, a member of the commission that recommended breaking the lease.

“From now on, the mosque should establish a sustainable relationship with Belgian authorities, while respecting the law and the traditions of our country, which convey a tolerant vision of Islam,” said Justice Minister Koen Geens in a statement.

Saudi Crown Prince Mohammed bin Salman, who will meet Tuesday with President Trump on a two-and-a-half-week visit to the United States, has said he wants to fight extremist interpretations of Islam long embraced by the royal family and to scale back the Saudi government’s backing for conservative mosques around the world.

The Belgian government’s decision to terminate the lease came after months of negotiation with the Saudi government. The Belgians did not say whether they were paying a settlement to the Saudis, and a spokesman did not reply to a request for comment. The Saudi Embassy in Brussels also did not reply to a request for comment.

Ahead of the announcement, a Belgian official who spoke on the condition of anonymity to describe the ongoing talks said the Saudi government was not fighting the effort to sever its ties to the mosque.