ANTWERP, Belgium — Normally, Dieter Moyaert and his soccer-loving friends liked nothing more than hanging out at the Cafe Royal, a soccer bar dominated by hard-core fans of Royal Antwerp, watching a match, downing beers and, in a few cases, slipping into the bathroom for a stronger substance.

On this particular weekend, though, things were different. Visible in the distance, the stadium lights had been turned on, and a crucial match against Lierse was about to start. But few people in this Dutch-speaking city in the Flemish north of the country seemed really excited.

It was right after the twin terrorist attacks in Brussels, and politicians in the capital had just canceled a protest march against fear, out of fear of more attacks. That, it seemed, was more than Mr. Moyaert and the other self-styled “soccer hooligans” in a group known as the Antwerp Casuals could stand.

In an interview this week, Mr. Moyaert said he called the leaders of the main rival hooligan groups and together they decided that on the day of the canceled march they would head to Brussels, the capital, where the French language dominates.