Three Belgian nationals arrested last week have been charged with attempting to commit terrorist murder and with taking part in the activities of a terrorist group, Belgium’s federal prosecutor has said. Nine other suspects arrested have been released.

Police had carried out about 40 house searches overnight. The arrests came shortly before many parties began across Belgium to watch live broadcasts of the country’s Euro 2016 group stage match against Ireland and there were reports that such events could have been the targets.

The federal prosecutor’s office said that homes and garages were searched in 16 municipalities, mostly in and around Brussels. The statement said there were no major incidents during the raids and no arms or explosives were found.

The prosecutor’s statement said that “the results of the investigation necessitated an immediate intervention”, indicating a violent attack was probably planned in the near future.