"We especially appeal to anyone who might have filmed or think they have photographed the suspect," spokesman Eric Van der Sypt said at a press conference in Brussels, where prosecutors presented a video showing the man's escape route from the devastated departure hall back into central Brussels.

Police have been desperately searching for the man ever since he was filmed next to the two suicide bombers who blew themselves up at Brussels airport on March 22 in coordinated attacks that also struck a metro station in the city. A total of 32 people died.

The newly released police video shows the suspect, wearing a hat and a light-coloured jacket, fleeing the airport's departure hall after the bombs went off at 07:58 am.

CCTV footage shows him continuing his route on foot towards central Brussels, where surveillance images lose sight of him at 09:50 am.

Along the way, the man discards his jacket and at one point appears to be on the phone.

Investigators are still looking for the jacket, described in a statement as "bright with a hood which is dark inside".

"Especially the jacket interests us," the prosecutor office's spokesman told reporters.

Potential witnesses are asked to contact the police using a specially provided phone number and email address.

The video can be seen at the following address: https://www.youtube.com/watch?v=eso1zW-eRqg