Mohamed Abrini, wanted over November's Islamic State attacks in Paris, has been arrested in Brussels, Belgium's public broadcasters said on Friday, adding that he was probably involved in last month's Brussels bombings.
Public prosecutors confirmed in a brief statement only that police had made several arrests related to the Brussels attacks.
Abrini, a 31-year-old Belgian, was "more than likely" the "man in the hat" seen on security camera footage at Brussels airport on March 22 with two suicide bombers, VRT and RTBF said on their websites, citing unidentified sources.
If confirmed, the arrests could mark a success for Belgian security services which have faced fierce criticism at home and abroad since Brussels-based militants organized the attacks that killed 130 in Paris on Nov. 13.
They took place a day after police issued new images and detail on the "man in the hat" and follow the arrest in Brussels three weeks ago of the prime surviving suspect in those attacks.
Four days after the March 18 arrest of Salah Abdeslam, with whom Abrini was seen driving towards Paris two days before the Paris attacks, brothers Brahim and Khalid El Bakraoui and a third local man Najim Laachraoui killed 32 people at Brussels airport and on a metro line running under EU institutions.
VRT and RTBF said Abrini was probably the man disguised in heavy glasses and a floppy hat who was pictured with Brahim Bakraoui and Laachraoui moments before the other two blew themselves up at the airport.
A second suspect held on Friday was believed to be a man seen with Khalid Bakraoui at a metro station shortly before the latter blew himself up on a train on the same line downtown.
VRT named the second man as Osama Kraiem. Broadcasters said he had also been caught on CCTV buying holdalls at a downtown mall which were later used in the Brussels bombings.
Abrini was arrested in the borough of Anderlecht, VRT said, next to the western district of Molenbeek which has been at the heart of Belgium's troubles with Islamist militants.
He had been on Europe's most wanted list since being seen on a motorway service station CCTV video driving with Abdeslam towards Paris from Belgium in a car used two days later in the attacks in which Abdeslam's elder brother was a suicide bomber.
The "man in the hat" left the airport shortly after the twin suicide bombings and was tracked on CCTV for several miles into the city center. On Thursday, investigators released new video footage of him and urged people to look for his discarded coat.
Wearing glasses and a hat, he had been very difficult to identify from the footage showing him pushing a laden luggage trolley alongside the two who blew themselves up with similar bags. A third bomb was later found abandoned at the airport.