Prosecutors released new footage of the so-called "man in the hat" on Thursday, as they ramp up efforts to find the third suspect behind the attack that killed at least 17 people at the city's airport on March 22.

"We especially appeal to people who might have filmed or taken a photograph of the suspect," said spokesman Eric van der Sypt.

"All information will be handled discreetly," he added.

New footage of third man

The newly reconstructed footage released by authorities showed the man leaving the airport - first walking, then running. He is then seen walking through the center of Brussels, in the area where the EU has many of its institutions.

At one point, the man is seen casting off his white jacket. "We're particularly interested in the jacket," said another spokesperson.

The "man in the hat" has been linked to the same terrorist cell behind the Paris terrorist attacks in November. The other two men involved in the Brussels airport bombing have been identified as Ibrahim El Bakraoui and Najim Laachraoui.

Following the airport bombings, another explosion killed at least 14 people in the metro. All in all, 32 people were killed and hundreds were injured in the March attacks.