Authorities in Belgium arrested 12 suspects as part of a large anti-terror investigation that involved questioning at least 40 people and raiding numerous properties, including 40 homes and more than 150 locked-up garages. No arms or explosives were found during the raids that took place in 16 municipalities but authorities said that an investigation had determined there was a need for “immediate intervention.”

Law enforcement officials were working off “a hypothesis” that terrorists had planned to target people who were going to gather on Saturday to watch live broadcasts of Belgium play Ireland in the European Championship. Still, a spokesman for the country’s federal prosecutor emphasized there was no solid proof that soccer fans were going to be targeted.

Despite the warnings, officials say the public events to watch the soccer match would go on as planned, even as more actions targeting potential terrorists were likely. “It will be the case in the coming hours that we will take additional and adapted measures,” Prime Minister Charles Michel said. The country is still at a threat level of three out of four, meaning an attack “is possible and likely.” Belgium has been living under that threat level since the March 22 attacks in Brussels that killed 32 people.

“It is not over. We remain under terror alert 3, it means that something is still up,” Interior Minister Jan Jambon said.