Belgium’s police forces are looking for several terror suspects, as the capital, Brussels, endures a second day of a security lockdown.
Interior Minister Jan Jambon said the current threat was greater than that posed by Salah Abdeslam, wanted for the Paris attacks.
Brussels is on its highest level of alert amid fears an attack.
The city was a base for the Paris attackers – Islamic State militants – who killed 130 people.
The security situation in Brussels is being reviewed and an announcement about whether the lockdown should continue is expected later in the day.
Metro services remain suspended, and residents have been told to avoid crowds.
Soldiers are patrolling the streets as a manhunt continued for Abdeslam, 26, a French national who lived in Brussels. Police describe him as armed and dangerous.
Friends said he was in the Brussels area and trying to get to Syria.
Interior Minister Jambon said the “terror threat in Belgium would not be over once Salah Abdeslam is out of harm’s way.”
“The threat is broader than the one suspected terrorist,” he told Flemish broadcaster VRT.
It was not clear if Jambon was referring to those involved in the Paris attacks, or others who might be planning attacks in Belgium.
Life in the city is expected to be unusually quiet again during the day. The city centre was almost empty on last night as restaurants and bars shut early.
The US embassy told Americans in the country to stay indoors and the US European Command issued a 72-hour restriction on travel to the city by all military personnel and contractors.