Police in Brussels on Sunday reported clashes and disturbances as around 5,500 right-wing and far-right protesters took to the street to voice their opposition to Belgium's decision to sign a United Nations migration pact.

Belgian Prime Minister Charles Michel's decision to sign the text adopted in the Moroccan city of Marrakesh prompted the right-wing Flemish N-VA party to pull its support for the government coalition.

Brussels police said around 5,500 people took part in the march against the UN pact, which took place outside key European Union buildings, while another 1,000 took party in counter-protests organized by left-wing parties and NGOs.

Security officials were forced to use tear gas and water cannons to disperse crowds as clashes erupted in the right-wing protests.

Former secretary of state for migration, Theo Francken, a member of the N-VA known for his outspoken anti-immigration views, published a video on Facebook in support of the action but asked that the protests be aimed at migration policy and not migrants.