“Police carried out two searches as part of a terrorism case linked to the arrest (near Paris) of Reda Kriket,” the prosecutor said in a statement.
French terror suspect Kriket was arrested in the outskirts of Paris on Thursday.
Kriket is suspected of having been in the “advanced stage” of plotting an attack on France and has been described by authorities as “extremely dangerous”.
After his arrest, police on Thursday conducted a raid on his home in the northern Parisian suburb of Argenteuil, finding ready-to-use explosives and several handguns.
In connection with Kriket's arrest, police on Friday carried out a massive anti-terror operation also in Schaerbeek and in Forest, both neighbourhoods in Brussels.
The prosecutor said two of the three men arrested during the raids had been injured in the leg.
Amateur video footage showed a man lying on the ground by a tram station holding a small backpack.
A total of 31 people were killed in the suicide bombings that struck Brussels airport and the city's Metro on Tuesday.
Connecting the dots between the Paris and Brussels attacks
Police in Belgium and Paris are still trying to connect the potential dots between the November 13 attacks in Paris – in which 130 people were killed – and those in Brussels. The picture is now getting somewhat clearer.
Kriket was on Friday linked to Abdelhamid Abaaoud, the suspected ringleader of the Paris attacks and who was killed by police five days after the carnage in the French capital.
Belgian police have also linked Salah Abdeslam – the only surviving jihadist directly involved in the Paris attacks and who was arrested in Belgium last week – to the Brussels suicide bomber brothers, Khalid and Ibrahim El Bakraoui.
On Friday, the Belgian federal prosecutor also confirmed that 24-year-old Najim Laachraoui – a bomb maker whose DNA was found on explosives used by the jihadists in Paris – had been among the three attackers who targeted the Brussels airport on Tuesday, saying he had died as one of the two suicide bombers who had struck there.
The third airport attacker is still believed to be at large, however, after his bomb failed to detonate.
Following the latest raids and arrests in both Paris and Brussels, French President François Hollande on Friday declared that the jihadist network behind the deadly attacks in the two cities are “in the process of being destroyed”, but warned that other cells remain,
“We have had some results in finding the terrorists and, in Brussels as well as Paris, there have been a number of arrests and we know that there are other networks,” he said.
“Even if the one that committed the attacks in Paris and Brussels is in the process of being destroyed… there is still a heavy threat.”