Belgian authorities opened an investigation on Tuesday after arsonists attacked a planned asylum seekers centre in the small town of Belzen raising fears of anti-migrant violence in Belgium.
The fire late Sunday, which did not cause any casualties, took place at a former retirement home whose scheduled change into an asylum centre sparked angry protests including by supporters of the far-right Vlaams Belang, one of the biggest parties in Dutch-speaking Flanders.
"This is the first time that a voluntary fire has been set at a reception centre" in Belgium, Benoit Mansy, spokesman for Fedasil, the federal agency for the reception of asylum seekers, told AFP.
Investigators said the cause of the fire was intentional, with Belgium's Migration Minister Maggie De Block decrying "a criminal act inspired by hatred and intolerance".
In addition to a criminal investigation, prosecutors are also probing whether laws curbing hate speech on the internet had been violated.
According to the newspaper De Morgen, several comments such as "Well done, keep it up", "finally someone who takes charge", have appeared on social media since Sunday.
The centre, managed by the Red Cross, was initially scheduled to receive 140 asylum seekers from December 15.
Despite information meetings with locals, the centre was contested in the area and triggered several protests. A photo on Twitter showed about 15 demonstrators behind a Vlaams Belang banner proclaiming "No asylum centre in Bilzen".