The area around the City2 shopping centre, a major commercial hub in the centre of the Belgian capital, was sealed off early today local time.
“A man was arrested at 5.30am this morning, possibly in possession of explosives. The bomb disposal team of the army is verifying whether this is the case,” a spokeswoman for the Brussels prosecutor said.
The incident triggered a meeting between Prime Minister Charles Michel and the national crisis response centre, which co-ordinates security measures.
Mr Michel admitted the situation was “very serious”.