Belgian federal police also released a 32-second video of a man in a hat seen in the company of the airport suicide bombers, indicating that he could still be at large.
It was not clear if the three suspects ordered to be held by an investigating magistrate were linked to the March 22 attacks in Brussels that killed 35 people and wounded some 270.
Those suspects — identified by Belgian prosecutors as Yassine A, Mohamed B, and Aboubaker O — were detained during 13 police searches on Sunday in Brussels and the northern cities of Mechelen and Duffel.
The Belgian Federal Prosecutor’s Office provided no details of the alleged actions committed by the suspects and said a fourth person also detained on Sunday was released without charge.
Yesterday, Belgian health minister Maggie De Block announced that four of those taken to hospital after the bombings at the airport and Metro had died.
She posted: “Four patients deceased in hospital. Medical teams did all possible. Total victims: 35. Courage to all the families.”
Ms De Block reported over the weekend that 101 of those wounded in the blasts were still being treated in hospitals, including 32 in burn units. A doctor at one of those burn units who had once served in Afghanistan described patients’ wounds as shocking.
One week after the devastating attacks, the airport is planning to test its capacity to partially resume passenger service, but it’s too early to say when service might actually resume, an airport official said.
The attack severely damaged the departure area.
Florence Muls, an airport communications manager, said 800 staff members today will test temporary infrastructure and new arrangements designed for passenger check-ins.
The Belgian government and firefighters must approve the new system before the airport can start handling passenger traffic again, she said.
Before the bombings, the airport served some 600 flights a day and 23.5m passengers per year.
Meanwhile, Turkey has prevented potential attacks in recent weeks including planned suicide bombings, president Tayyip Erdogan’s spokesman said yesterday, following a spate of attacks blamed on Islamic State and Kurdish militants.
Ibrahim Kalin made the comment at a news conference in Ankara. Turkey has been hit by four bombings this year that have killed more than 80 people. The most recent on March 19 in Istanbul, killed three Israeli tourists and an Iranian.
Israel has urged its citizens in Turkey to leave “as soon as possible” in an upgraded travel advisory predicting possible follow-up attacks.