Europe is on high alert following anti-terror raids and arrests of suspected Islamist militants.
More than 20 people have been arrested in Belgium, France and Germany and Belgium has joined France in deploying troops alongside police.
Security has been tightened in several countries after last week’s attacks in Paris left 17 people dead.
There are increased concerns about the return of young Europeans who have gone to fight with Middle East militants.
In Belgium, five people were charged on Friday with “participating in the activities of a terrorist group” following a series of raids that began on Thursday evening and left two suspects dead.
Guns, munitions and explosives, as well as police uniforms and a large amount of money, were all seized by police during the operation.
Eric Van Der Sypt, an official at the prosecutors’ office, told AFP that: “The investigation… has shown that these people had the intention to kill several policemen in the street and at police commissariats [police stations].”
Thirteen people were arrested in total but only five would be prosecuted, he said. Belgium would also seek the extradition of two suspects held in France.
On Friday, the Belgian government also announced new measures to deal with terrorist suspects.
They include making travelling abroad for terrorist activities a crime and expanding the cases where Belgian citizenship can be revoked for dual nationals who are thought to pose a terror risk. BBC