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.
Police and prosecutors have been declining all comment but will hold a news conference at noon.
La Derniere Heure newspaper and broadcaster RTL earlier said Laachraoui had been arrested in the Anderlecht district of Brussels, adding that he was the third man pictured in airport CCTV footage alongside two suicide bombers who blew themselves up on Tuesday.
Belgian media earlier said that brothers Khalid and Ibrahim El Bakraoui had been identified as two of the bombers who struck the airport and the Maalbeek metro station in Tuesday's Brussels attacks.
This combination of handout pictures obtained via Interpol shows
Khalid (L) and Ibrahim El Bakraoui, the two Belgian brothers
identified as the suicide bombers who struck Brussels on Tuesday.
Belgian investigators named Laachraoui on Monday following the arrest of Paris suspect Salah Abdeslam.
They said that under the alias Soufiane Kayal he travelled to Hungary in September with Abdeslam, who is the last known survivor of the 10 Paris attackers.
Laachraoui is also believed to have travelled to Syria in February 2013.
Traces of DNA from the 24-year-old were found on the explosives used in the gun and suicide attacks in Paris, a source close to the French investigation said earlier this week.
Belgian prosecutors on Monday said Laachraoui's DNA had been found at an apartment in the Schaarbeek district of Brussels where bomb making equipment and one of Abdeslam's fingerprints had been found in December.
His DNA was also found at an apartment used by the Paris attackers in Auvelais, near the central Belgian city of Namur, which he had rented under a false name.
