The city’s underground metro service will not be running Saturday and other public transit will be operating on a limited schedule, the ministry said.
As news of the warning spread, Belgian authorities said they arrested one person Friday as part of investigations into the deadly November 13 Paris attacks.
The arrest happened in the impoverished Brussels suburb of Molenbeek. The person’s home was searched, and a few weapons were found, but no explosives, Belgium’s federal prosecutor’s office said. No further information about the arrest was released.
Referring to Brussels’ alert level, Belgian Prime Minister Charles Michel said then authorities’ prime objective is to reduce the number of large events in order to free up police officers to secure Brussels.
Michel added that “given the large number of people” taking the subway, the Crisis Centre of the Belgian Interior Ministry recommended that service halt until Sunday afternoon, when the next evaluation takes place.
Outside of Brussels, the rest of the nation will maintain its current terrorism level.
If people take the alert seriously, Brussels will be “shut down” Saturday, CNN terrorism analyst Paul Cruickshank said.
“It suggests they have something specific and credible at the intelligence front pointing them in the direction that there may be a terrorist plot in the works,” he said.