Scores have been killed and wounded after explosions tore through Brussels airport and a metro station in the centre of the city.
Reports from Kurdish media said the terror group had admitted being behind today’s strike, Express reported.
Security experts and a leading European government minister have also suggested ISIS are to blame for the Brussels atrocity.
Today’s multiple blasts come just days after the arrest of Salah Abdeslam in the Molenbeek district of the Belgian capital.
Experts are now warning that today’s terror attacks could be a revenge strike after the suspected Paris massacre mastermind was detained in a dramatic police raid in which he was shot in the leg.
While no group has yet claimed responsibility for the Belgian attack, Spanish Foreign Secretary José Manuel García Margallo immediately laid the blame with ISIS - also known by its Arabic acronym Daesh.
He said: "Let's stop pretending, let's worry about Daesh, which is the enemy.”
Describing the group as a “terrorist cancer”, he said: "We must be aware that as they are hit in Syria and Iraq, they are going to go elsewhere.
“They have sleeper cells all over the world and Belgium has a very serious problem.”
Abdeslam, who is thought to be responsible for planning the French attacks, is currently being questioned by Belgian security services.