The key remaining suspect in November's Paris terror attacks, Mohamed Abrini, has been arrested in Belgium, prosecutors confirmed.
Belgian media say Abrini is also likely to be the "man in the hat" seen on CCTV before bomb blasts in the Brussels airport departure hall on 22 March.
Five arrests were made on Friday. One suspect, Osama K, will be investigated over the bomb attack on the metro that followed the airport bombing.
The two attacks left 32 people dead.
The gun and bomb attacks in Paris on 13 November killed 130 people.
Amateur footage said to be of Abrini's arrest shows a man being bundled into a car in Place Albert in the Anderlecht district of Brussels.
Abrini had not been directly linked to the Brussels attacks until now.
Belgian investigators confirmed at a press conference that Abrini was among those detained. Two more suspects were arrested along with him.
Investigators said the fourth arrested man, named as Osama K, was being investigated for helping suicide bomber Khalid el-Bakraoui at the Maelbeek metro station.
The prosecutor's office said he had been filmed in Brussels buying sports bags used to hide the airport and metro station bombs.
The authorities had on Thursday released new video footage of the so-called "man in the hat", appealing for the public's help in finding him.
The individual in the footage was seen beside the two suicide bombers at Brussels airport. He left the scene shortly before the blasts.
At the press conference, the investigators said they were trying to determine whether the "man in the hat" was Abrini.
