Authorities have identified a Belgian named Oussama Atar as the possible organizer of deadly Islamic State attacks on Paris and Brussels over the past year.

A judicial official and a security official said Tuesday that Atar's name appears in the investigation. The judicial official said there is evidence that Atar is the real identity of Abu Ahmed, a pseudonym of the suspected attack coordinator. His whereabouts are unknown.

The officials spoke on condition of anonymity to be able to discuss the ongoing investigation.

Atar's name has been circulating in Belgium for months as possibly linked to the attacks. Belgian prosecutors would not comment Tuesday.

Investigators believe the same IS cell was behind the Paris attacks in November 2015 and the Brussels attacks in March, which together killed 162 people.