Belgian federal prosecutors on Saturday said they had charged three men, including a suspect Belgian media believe is a man captured on security footage with two suicide bombers at Brussels airport on Tuesday.
This man, named only as Faycal C and who media say was the man wearing a hat and a light jacket in the picture at the airport, was charged with taking part in the activities of a terrorist group and actual and attempted terrorist murder.
The prosecutor's statement said no weapons or explosives had been found during a search of his home.
Two other men, Aboubakar A. and Rabah N., were also charged with terrorist activities and membership of a terrorist group. Rabah N. was wanted in connection with a related raid in France this week that authorities say foiled an apparent attack plot.
Prosecutors also said they were holding a further man, Abderamane A., for an extra 24 hours. He was detained following a series of raids after this week's bomb blasts at Brussels airport and on a rush hour train.
Another person, Tawfik A., taken in for questioning on Friday, was released.
Earlier on Saturday Belgian media had named the third man seen at the airport with two bombers on Tuesday as Faycal Cheffou and said he was a freelance journalist.
Le Soir newspaper said Cheffou was identified by a taxi driver who drove the attackers to the airport. Earlier it had quoted police sources as saying it was highly likely he was the third man seen at the airport.
Nine people in total have been arrested since Thursday in Belgium and two in Germany, as European authorities swoop on Islamic State militants they link to the bombings at the airport and the metro in Brussels that killed 31 people and to the attacks in Paris last November that killed 130.
The brother of one of the two suicide bombers who died at the airport killed himself in the bomb on the metro.
Meanwhile, in Germany there are renewed calls for better data sharing.
Europe urgently needs to improve the way its security agencies share information, members of German Chancellor Angela Merkel's conservatives were reported as saying, stoking a debate on how to tighten security while safeguarding data protection.
The suicide bombings in Brussels on Tuesday that killed 31 people and last November's attacks in Paris have highlighted weak links in information-sharing between Western intelligence services.
"Faster communication is important so that tips about possible attacks can be quickly assessed and terrorist acts can be prevented if possible before they take place or cleared up in a more focused way," Germany's EU Commissioner Guenther Oettinger told the daily Bild.
Oettinger, a member of Merkel's Christian Democratic Union, called for data protection rules to be standardized to make it possible for security agencies in other EU member states can access data.
"It can't be that we collect data in Germany and that investigations in other countries fail because they are not allowed to look at it. We need a security union," he said.
Following the Brussels attacks, Interior Minister Thomas de Maiziere said security should be given a priority over data protection, prompting criticism from the opposition Greens.
Germans are particularly sensitive about data protection because of their experience of state surveillance by the Stasi secret police in East Germany and the Gestapo under the Nazis.
But Hans-Peter Uhl, a member of the Christian Social Union, sister party to Merkel's CDU, backed de Maiziere and described the debate as "grotesque."
"Bombs are exploding and we are concerned about data protection," Uhl told Die Welt. "Now it needs to be recognized that Europe is not just an area of freedom but must prioritize becoming an area of security and justice again."
German fears that an attack could happen in their country have risen since the Paris attacks and the head of its domestic intelligence agency has warned that Islamic State militants have slipped into Europe disguised as refugees.
Greens co-chairwoman Simone Peter told Die Welt that Europe's security agencies needed to improve co-operation but said the quality of data was more important than quantity.
"Basic rights like data protection are not a luxury that you can jettison when it gets difficult," she said. "More groundless surveillance will be of less use than the targeted collection and evaluation of suspicious factors." \
(Editing by Hugh Lawson)
(Editing by Philip Blenkinsop and Richard Balmforth)