Thousands of people marched in Brussels on Sunday against a UN pact aimed at fostering cooperation on migration with security forces firing tear gas and water cannon after some refused to disperse.

The demonstration eclipsed a smaller one in support of the migration deal, the signing of which brought down Belgium’s government last week.

Police said some 5,500 people marched in the bigger protest organised by Flemish right-wing parties in the part of the capital where main European Union institutions are located.

Local authorities initially banned the protest for fear of violence erupting, but Belgium’s high court overturned the ban, citing the right to protest peacefully.

However, police had to use tear gas and water cannon on protesters after some became violent when they were asked to leave.

A separate counter-demonstration of about 1,000 people, organised by left-wing groups and non-governmental organisations, took place in the city centre.

Belgian right-wing N-VA, the biggest party in parliament, pulled its ministers from the ruling coalition last week after Prime Minister Charles Michel refused its demand that he not sign the UN migration compact in Marrakech.

Opening salvo

Michel secured a large parliamentary majority in favour of maintaining Belgium’s support of the UN text, with support from the opposition socialists and greens. Critics said the N-VA’s move was the opening shot in a campaign before federal elections in May.

The UN pact was agreed to in July by all 193 UN members except the United States, but only 164 formally signed it at the meeting last Monday.

It has run into criticism from European politicians who say it could boost immigration to Europe as the bloc has turned increasingly restrictive on accepting refugees and migrants since a 2015 spike in arrivals.

Ten countries, mostly in formerly Communist Eastern Europe, have pulled out of the non-binding pact.

With a record 21.3 million refugees globally, the UN began work on the pact after more than one million people arrived in Europe in 2015, many fleeing civil war in Syria and poverty in Africa.