Tens of thousands of people took to the streets of Brussels on Thursday to show their support for Catalan independence, weeks ahead of a regional election that would see it regaining autonomy from the Spanish government.

By the time the demonstration was underway, the Brussels police said 45,000 people clad in the yellow, red and blue of the independence movement’s flag gathered in the Cinquantenaire park despite the usual rain.

The demonstration was partly in support of exiled and disputed Catalonia President Carles Puigdemont, who fled to Belgium and is resisting extradition attempts, the Independent reported.

“If the mountain will not come to Muhammad, then Muhammad must go to the mountain,” Carles and Rosses, a couple from Catalonia at the demonstration, told Efe news.

Besides private vehicles and commercial flights, organisers said 250 buses and at least five chartered flights had been organised to transport demonstrators from Catalonia to Belgium.

The march started at the Cinquantenaire Arcade, built to commemorate the 50th anniversary of Belgium’s independence, and was set to move around the European Quarter, a district in Brussels that holds many European Union institutions.

The route, expected to finish close to the European Parliament, brought protesters just around the corner from the European Commission, where its Vice President Frans Timmermans told a press conference that the atmosphere he had witnessed was very positive and determined.

The demonstration was organised by Omnium Cultural and the Assemblea Nacional Catalana, two pro-independence groups, and was attended by political figures from the region, including the deputy leader of the Republican Left of Catalonia (ERC), the party currently leading the polls for the December 21 election.

Following the region’s unilateral declaration of independence on October 31, the Spanish government triggered Article 155 of the Constitution, which saw Catalonia’s autonomy reeled back and its Parliament dissolved.

Puigdemont faces charges of sedition, rebellion, misuse of public funds and disobedience in Spain, though the charges were brought against him after he fled to Belgium along with four of his Cabinet ministers.

Several other members of the Catalan government, including former Vice President Oriol Junqueras, remain in preventative prison in Spain as they await trials for sedition and rebellion.