Police had used force to break up an unlicensed protest when it began on Tuesday outside the city offices that deal with the registration of foreigners. They arrested 130 people.

"We approve demonstrations when we can," a spokesperson for Brussels' mayor's office said. "But in this case we did not receive a request. The demonstrators setup tents with the intention of staying for 24 hours. The security and sanitary conditions were not respected."

Demonstrators, mainly foreigners, have regularly protested in Brussels to start a political dialogue aimed at providing legal status to foreigners without Belgian residency permits. This is the first time the protests ended with a large number of arrests.

The majority of those taken into custody were held overnight in the Palace of Justice, Belgian media reported. Two lawyers accompanying the demonstrators were also manhandled by police, according to media reports.

The migrants face penalties for taking part in the unlicensed demonstration and they could also be deported, according to a spokesman for an organization that defends the rights of foreigners in Belgium.