Belgian media which earlier reported the arrest on Wednesday of a prime suspect in Tuesday's bomb attacks in Brussels said the person detained was not, in fact, Najim Laachraoui.
La Libre Belgique newspaper said another person had been arrested. DH, which first reported the story, also said the man detained in the Anderlecht district had been misidentified.
Laachraoui, 25, was already sought by the police since Monday, Belgian newspaper DH says.
His DNA had been found in houses used by the Paris attackers last year, prosecutors said on Monday, and he had travelled to Hungary in September with Paris attacks prime suspect Salah Abdeslam.
Laachraoui is also suspected of being responsible for the bombs used in the Paris massacre in November after his DNA was found on suicide belts used in the Bataclan Theatre and the Stade de France.
The two suicide bombers who struck at Brussels airport have been named by Belgian state broadcaster RTBF as brothers Khalid and Brahim El Bakraoui.
Citing a police source, RTBF said the brothers who were Brussels residents were known to the authorities but for involvement in organised crime rather than terrorism.
Khalid, under a false name, had rented the flat in the Forest borough of the Belgian capital where police killed a gunman in a raid last week, RTBF said.
Investigators found after that raid an Islamic State flag, an assault rifle, detonators and a fingerprint of Abdeslam's, who was arrested three days later.
Investigators are focusing on whether CCTV footage captured moments before the airport blasts shows two of the three suspected terrorists wearing single gloves to secrete detonators.
Zaventem's mayor said the explosives were stowed in their luggage and detonated before reaching the security gate.
