Belgian police arrested three people on Saturday in raids in a poor, immigrant quarter of Brussels as they pursued emerging links between the Paris attacks and an Islamist bastion in France's northern neighbor.
Prime Minister Charles Michel said at least one of those held from the inner Brussels neighborhood of Molenbeek was believed to have spent the previous evening in Paris, where two cars registered in Belgium were impounded close to scenes of some of the violence, including the Bataclan music hall.
"Police operations will go on," Michel told RTL television as local media reported continued security activity overnight in Molenbeek, west of the city center, which is home to many Muslims, notably families originally from Morocco and Turkey.
A French prosecutor said a car hired in Belgium was linked to the attacks and that a Frenchman living in Brussels rented it and was later stopped early on Saturday at the Belgian border.
Proportional to its 11 million population, of whom half a million are Muslim, Belgium has been the European country which has contributed the most foreign fighters to the civil war in Syria - over 300 by official estimates a year ago - and it has figured in many Islamist attacks and plots across the continent.
Molenbeek has been connected with two attacks in France this year alone. Security officials have said the Islamist who killed people at a Paris kosher grocery in January at the time of the attack on the magazine Charlie Hebdo acquired weapons in the district. So too did the man overpowered in August on a Thalys high-speed train from Brussels to Paris before he killed anyone.
An alleged plot to attack Belgian police stations in January, which was broken up by raids in which two men were killed in the eastern town of Verviers, had connections to Molenbeek. And a Frenchman accused of shooting dead four people last year at the Jewish Museum in the Belgian capital also spent time in the area.