On Tuesday, March 22, a series of three coordinated attacks left 31 people dead and 270 wounded in Brussels, Belgium. The first two explosions occurred just before 8:00am local time in the departure hall of Zaventem Airport, killing 14 people. At least one of the explosions was believed to be a suicide bombing. There were also reports of gunfire and shouting in Arabic before the detonations. Police later found an undetonated suicide belt and a Kalashnikov assault rifle at the airport. Approximately one hour later, a third explosion occurred in the middle carriage of a metro train as it was pulling out of Maelbeek station, which is located in close proximity to several European Union buildings. The blast, which is also believed to be the result of a suicide bombing, killed 20 people. The Islamic State in Iraq and the Levant (ISIL) claimed responsibility for the attacks in a statement released by its Amaq news agency, stating they carried out the attack using “explosive belts and devices.” They also referred to Belgium as a “country participating in the international coalition against the Islamic State.”
Following the attacks, flights to and from Brussels were suspended and the metro system was shut down. Residents and visitors to Brussels were initially advised to stay inside as several counterterrorism raids were underway targeting individuals who may be linked to the attacks. Nuclear plants in Doel and Tihange were partially evacuated due to the heightened threat level in the country with only key personnel remaining on the premises.
Belgian authorities have identified two of the suicide bombers, Ibrahim el-Bakraoui and Khalid el-Bakraoui as brothers with criminal records. At this time, authorities are searching for the man caught on security camera at the airport, his idenity remains unknown.
The threat level in Brussels has been heightened since the ISIL-led attacks in Paris last November. Given the city’s designation as the headquarters of the European Union and NATO, it is a symbolic target for terrorists opposed to Europe’s participation in the U.S.-led coalition against ISIL. There is also speculation that the attack may have been linked to the recent arrest of Salah Abdeslam in Brussels on Friday. Abdeslam is the only surviving member of the ISIL team that carried out the Paris attacks. Early reports are stating that the explosive used in today’s attacks was likely Triacetone Triperoxide (TATP), which was also used in the Paris attacks and is favored by ISIL. TATP is made from readily available products that can be easily obtained, although it is unstable and can prematurely detonate if not handled properly. Traces of TATP were also discovered during recent raids targeting the Brussels terror cell involved in the Paris attacks, which could indicate the presence of a skilled bomb-maker and functional bomb-making facility in the area.
The Brussels attacks are consistent with ISIL’s recent tradecraft, using combined tactics and coordinated attacks to create mass casualties and hinder the emergency response by dispersing first responders to multiple locations. These attacks were aimed at soft targets, including public transportation and the check-in area of the airport, both of which lack a hardened security perimeter. The airport check-in area where the first attack took place is particularly vulnerable as it is accessible to the public without passing through a security checkpoint. This highlights the importance of expanding a facility’s security perimeter and employing a layered security approach. Soft targets can also be hardened by increasing the visibility of security measures in vulnerable areas where people gather.
At this time, ISIL remains a significant threat to Europe, especially in a country such as Belgium, which has contributed more foreign fighters per capita to Iraq and Syria than any other European country. As a result, militants with European citizenship have been able to return home without detection to carry out attacks in Europe, as was the case in Paris. Limited information sharing between European governments has exacerbated the threat, allowing militants to slip across borders. This type of attack, formulated by a functional ISIL cell, is unlikely in the U.S.; however, out of an abundance of caution several major cities, including New York, have increased security at vulnerable locations such as public transportation hubs, iconic locations and religious institutions. In the short term, the greatest threat to the U.S. continues to be lone-wolf and small group actors that may be inspired by the incident in Brussels.