ISIS claimed responsibility for the bombings in Brussels, Belgium, that killed at least 31 people on March 22.
In a news conference, Belgian Prime Minister Charles Michel said his country had been "fearing terrorist attacks," and called the bombings "blind, violent, cowardly." Just hours after the attack, an ISIS-affiliated news agency stated in a bulletin the terrorist group had taken responsibility for the attacks, The New York Times reported.
"Islamic State fighters carried out a series of bombings with explosive belts and devices on Tuesday, targeting an airport and a central metro station in the center of the Belgian capital, Brussels, a country participating in the coalition against the Islamic State," the bulletin read.
"Islamic State fighters opened fire inside the Zaventem airport, before several of them detonated their explosive belts, as a martyrdom bomber detonated his explosive belt in the Maelbeek metro station.”
Intelligence officials believe the attacks were "revenge" for the arrest of failed Paris bomber Salah Abdeslam in Brussels just days ago, as well an act of fear that Abdeslam would betray the Islamic State, according to the Daily Mail.
Intelligence officers told the Daily Mail the fact that Abdeslam refrained from killing himself during the Paris attacks by a suicide vest became a cause for concern among jihadists.
"This showed a weakness, a desire to live which would have been played on during questioning," an anti-terror specialist told the Daily Mail.
"He was not a man showing inner strength and the capacity to withstand interrogation, this meant that if those involved in today’s attacks were known to him they believed they had to activate their plans before they too were arrested and their weapons seized."
The attacks included two incidents in different parts of the city, one consisting of two explosions in Brussels airport and one an hour later at the Maelbeek subway station.
Andrew Carroll, who was in the subway station at the time of the attack, described the events and said his decision to sit in the back of the car contributed to his survival.
"I always take the smaller exit which leads to Chaussee d’Etterbeek, which is near the back and is closer to my office. Most people go through the larger exit which leads out onto Rue de la Loi, which is the main thoroughfare leading to the European Commission and Council headquarters," he said.
"I arrived in Maelbeek at the usual time and hopped straight onto the escalator. A few seconds later I heard two sharp banging noises which seemed to come from behind me, and there was a sudden rush of heated air. Immediately, the escalator stopped, the lights went out and dust rained down from the ceiling. I heard several screams, and we all started running upstairs and out into the street."