A man has been charged with terrorist offences, in connection with March 22 attacks in Brussels that left 31 dead, including three bombers, Belgian prosecutors say.

The man was named as Faycal Cheffou and was arrested on March 24.

At least half the victims died at the airport, the rest in an attack on the metro in suicide bombings claimed by ISIS.

Meanwhile a demonstration against the attacks, planned for March 27 in central Brussels, has been canceled after a request from the authorities.

Organizers said people’s security was a top priority.

Belgian prosecutors said that Faycal C had been detained outside the prosecutor’s office in Brussels on March 24. A search of his home had found no weapons.

Faycal C was charged with “participation in the activities of a terrorist group, terrorist murders and attempted terrorist murders,” a statement said.

It gave no further details and made no comment on Belgian media reports that he was the third man in an airport CCTV image that showed the two suicide bombers – Najim Laachraoui on the left, and Brahim el-Bakraoui. Belgian media say the third man is Faycal Cheffou, a freelance journalist.

The third man, wearing a hat and pale jacket, also had luggage packed with explosives. However, he was said to have fled without detonating his device. It was detonated in a controlled explosion once the departures hall was cleared.

Brahim el-Bakraoui’s brother Khalid carried out the Maelbeek metro attack.

Faycal C was among 12 people arrested on March 24 and 25 in police raids in Belgium, France and Germany.

Four days before the Brussels attacks, the key suspect in the November 13 Paris attacks which killed 130 people, Salah Abdeslam, was detained in a raid in Brussels. Police said he was initially co-operative.

Belgian Justice Minister Koen Geens later confirmed in parliament that Salah Abdeslam “no longer wants to talk since attacks” in Brussels.

Separately, Brussels airport authorities said the “investigative work related to the judicial inquiry into the airport terminal has been completed” but that passenger activity could not resume before March 22.

Airport engineers and technicians are getting access to the terminal for the first time since the attack.

They will assess the damage and stability of the building. The airport authorities will also put new security measures in place.

The check-in area suffered severe damage when two blasts seconds apart hit opposite ends of the departures hall.

In addition to the dead, 340 people were injured. One hundred and one remain in hospital, of whom 62 are in intensive care.

In his weekly address on March 26, President Barack Obama paid his respects to the victims and said attempts to stigmatize Muslim-Americans should be rejected.

Meanwhile, Mariah Carey has canceled a concert scheduled for Brussels on March 27, citing security concerns.

In a separate development, Belgian prosecutors denied the murder of a security official at the Fleurus nuclear research centre was a terrorist act, the Belga news agency reported.