A manhunt was under way on Tuesday night for a suspected Islamic State terrorist involved in the twin attacks on Brussels' airport and a subway station in the heart of the city that killed at least 31 people and wounded more than 200.
The Islamic State claimed responsibility for the attack, which came only four months after the Paris terrorist attacks that killed 130 people. As Brussels was locked down, a police sweep found a bomb loaded with nails, chemicals and an Islamic State flag in a Brussels house.
Police issued a wanted notice for a young man in a hat who was caught on closed-circuit television pushing a laden luggage trolley at Zaventem airport alongside two others who, investigators said, later blew themselves up in the terminal, killing at least 11 people. The massive metro blast killed at least 20 commuters.
Belgian Prime Minister Charles Michel called Tuesday a "black day" for the country, adding: "What we feared has happened."
The blasts delivered the chilling message that the terrorists could hit the very headquarters of the EU. The attack at the Maelbeek Metro stop was only a few hundred metres from the vast office buildings, where EU policies, such as refugee admissions, are designed.
It also told Europeans that no city was safe from terrorists. Brussels has been on alert since the Paris attacks, and on higher alert since Friday, when a shootout in the Belgian capital ended in the capture of Salah Abdeslam, the main surviving suspect in the Paris attacks.
Belgian Interior Minister Jan Jambon had said on Monday the country's security forces were on high alert for a possible revenge attack following the arrest of Mr. Abdeslam, 26, a French citizen who was born and raised in Brussels. "We know that stopping one cell can … push others into action," he said. "We are aware this is the case."
The attacks will intensify the damage already inflicted on the troubled EU integration project and its once-steadfast devotion to open borders and passport-free travel. It will also call into question the effectiveness of the region's intelligence and security forces.
The failure of the intense security crackdown, launched after November's terrorist attacks in Paris, to track and arrest the terrorists before their murderous mission has rattled nerves across the continent. The police and military presence in EU's capital cities, from London to Rome, was intensified immediately after the Brussels explosions.
"This wasn't a one-off … it reflects a broader, more extensive network," Michael Hayden, a former director of the U.S. Central Intelligence Agency and the National Security Agency, said at the International Aviation Summit in Washington. "The network still exists and it's probably a lot smaller than many North Americans fear but clearly bigger than the Belgian police know about."
Brussels quickly went into lockdown. All flights and train travel to and from the city were cancelled and public transit was shut down.
Photos and video in the immediate aftermath of the airport explosions showed hundreds of people streaming out of the terminal building, some of them covered in blood from shattered glass and dust from the collapsed ceiling.
Authorities released a photo from CCTV footage of three men pushing luggage carts in the airport. Two of three men "very likely committed a suicide attack," Belgian federal prosecutor Frédéric Van Leeuw said at a late-afternoon news conference in Brussels. The two men believed to be the suicide attackers apparently were wearing dark gloves on their left hands.
Police were searching the city for the third man, who instantly became the most wanted fugitive in Europe, as several raids were carried out across the country. In the photo, the man is wearing a white or beige jacket, a dark hat and glasses.
The attacks came as the EU was already under enormous stress from the refugee onslaught, a referendum that could remove Britain from the EU and an eight-year-old financial and unemployment crisis that is still shaking the EU's foundations. Instant polls conducted after the Brussels attacks showed that support for Britain's exit – or Brexit – in the June 23 referendum has climbed. Many Britons are convinced that Britain must leave the EU if it is to gain full control of its borders.
Even before the attacks, the crowning achievement of the EU – the open borders among 22 of its 28 countries, known as the Schengen Area – was under threat from the refugee crisis and from demands for secure borders after the November attacks in Paris. After that massacre, France and Belgium, the home of some of the key Paris attackers, put up border controls that were also put up, along with fences, in several countries in southeastern Europe to try to stem the flow of refugees to the EU.
Tuesday's attacks showed the massive police presence in Brussels, the forensic evidence used to track Mr. Abdeslam and presumably others connected to terror networks, and the intelligence sharing among police forces across the EU came up well short.
The attacks created pandemonium in Brussels.
Elena Chad, a Russian-born Canadian who was to fly to New York on Tuesday morning, was in the airport when the blasts occurred, but had gone through the security checks and was far enough way that she did not hear them.
"When people learned about the explosions, they went crazy and ran into each other," she told The Globe and Mail. "We ran into a small corridor and were getting crushed, but we got outside."
Transferred to an airport warehouse, then to a sports centre in a small town near the airport, it took her 10 hours to get back to her Brussels home.
When the employees of the massive Thon Hotel EU in central Brussels heard a loud bang shortly after 9 a.m. on Tuesday, they immediately suspected it was no accident.
"By then, we knew about the explosions at the airport, so we feared the bang would be bad news," Hans Van Der Biesen, 39, the general manager of the 405-room hotel, told The Globe.
Hotel employees ran outside and saw smoke billowing from the Maelbeek Metro stop only about 20 metres away. Within minutes, the lobby had filled with bomb victims, some bleeding heavily, others with obvious flesh burns. "About 40 to 50 people were in the lobby, all wounded and triage was done here," Mr. Van Der Biessen said. "But it was strangely quiet; people were in shock."
The hotel's first-aid team tended to the wounded and stepped back when a fleet of ambulances and medics arrived and took the victims to the hospitals, with the most badly injured going first. Mr. Van Der Biesen does not know if all the victims survived.
Security officials warned that the final death toll of the attacks, which stood at 31 by Tuesday night, could rise. The tolls were vague because of the carnage at both sites.
With a report from Takara Small in Washington and Reuters