Islamic State suicide bombers brought terror, chaos and bloodshed to the city at the heart of European unity on Tuesday, detonating their nail-spewing bombs at an airport departures hall and on a subway train in attacks that left at least 34 people dead and prompted authorities to launch an intensive manhunt for at least one suspected accomplice.
The bombings paralyzed Brussels, the headquarters of the European Union and NATO, prompted international travel warnings to avoid Belgium and reverberated across the Atlantic to the United States, where New York and other major cities raised terrorism threat levels.
The wanted man accompanied two of the bombers to the airport, along with luggage bulging with explosives. Authorities were also hunting a suspected Belgian bombmaker who trained in Syria with the Islamic State and who later sneaked back into Europe.
Tuesday’s mass killings add this city to an ignominious but growing list of European capitals that have been struck in the past year by deadly attacks either perpetrated or inspired by the Islamic State, including Paris and Copenhagen.
Authorities had been bracing for an attack in Belgium for months as the country has struggled to stem a tide of homegrown extremism and as the Islamic State has repeatedly threatened to hit Europe in its core.
But when the attacks finally came, the magnitude was stunning. The day’s violence represented the worst on Belgian soil since World War II.
“What we had feared has happened,” said Belgian Prime Minister Charles Michel. “This is a black moment for our country.”
The apparently coordinated explosions created a renewed sense of threat that spilled far beyond Brussels, as authorities boosted police patrols in cities such as Paris, London and Washington.
The targets appeared to have been chosen for their symbolic value and for their ease of access.
The attackers first struck with twin bombings at the international airport, where early-morning travelers were preparing to board flights linking Brussels to cities across the continent and around the world. An hour later, a subway car transiting directly beneath the modernist glass-and-steel high-rises that house the European Union burst with smoke and flame.
In addition to the dead, about 250 people were injured, Belgian officials said.
Many of the injured lost limbs as shrapnel from the blasts radiated through packed crowds. Cellphone video recorded in the minutes after the airport blasts showed children cowering on a bloody floor amid the maimed and the dead. Footage from the subway revealed desperate scenes as people dressed for a day’s work stumbled from the mangled wreckage into a smoke-drenched tunnel.
Authorities acknowledged that they had been readying for an attack. But nothing like this, they said.
“We never could have imagined something of this scale,” Interior Minister Jan Jambon told Belgian television station RTL.
More attacks feared
And even as the country tried to recover from the trauma of Tuesday’s strikes, there was evidence that more could be on the way.
The Islamic State group has issued an updated communique taking credit for the Brussels attacks and threatening other countries taking part in the anti-IS coalition.
The statement promises “dark days” for countries allied against the Islamic State, threatening that “what is coming is worse and more bitter.”
The communique was published in Arabic and French, and an English translation was provide by the SITE Intelligence Group, which monitors jihadi websites.
IS also released photos purportedly showing its fighters in Syria giving out candy to children to celebrate the Brussels attacks, according to SITE.
The man being sought by police accompanied two of the bombers to the airport, according to a senior Belgian official who spoke on the condition of anonymity to discuss sensitive details of the case. The taxi driver who transported them said they were hauling particularly heavy luggage that investigators believe was packed with explosives.
At an apartment in the Schaerbeek area of Brussels, investigators later found explosive devices loaded with nails and chemicals, along with an Islamic State flag, the Belgian federal prosecutors’ office said in a statement.
“It was exactly the same type of bomb as at the airport,” the senior official said.
Belgian police released surveillance images of three men pushing luggage carts at Brussels Airport. The prosecutor’s office said that two of them — dressed in black with black gloves on their left hands, likely to conceal detonators — had blown themselves up.
But the third, dressed in white, was on the loose. His identity was unknown, and despite a nationwide hunt — with heavily armed officers combing the streets, and checkpoints at Belgian borders snarling traffic for miles — the suspect remained at large Tuesday night.
Across the continent, authorities were also hunting 24-year-old Najim Laachraoui, a suspected Islamic State bombmaker, according to two European security officials.
Laachraoui, a Belgian who was born in Morocco and raised in the Schaerbeek neighborhood, is believed to have trained in Syria and then returned to Europe. His DNA was found on one of the explosives belts from last November’s Paris attacks, and he is thought to have traveled at one point with Salah Abdeslam, the only surviving suspect believed to have played a direct role in the Paris massacre.
Tuesday’s attacks came only four days after Belgian counterterrorism authorities cheered the arrest of Abdeslam, 26, who was the most wanted man in Europe for the past four months. Abdeslam was discovered hiding in a Brussels apartment building in the Molenbeek neighborhood near the center of the city. After the raid, officials said they had uncovered a web of suspects much broader than they had previously imagined.
The latest bloodshed made clear that European capitals remain perilously vulnerable despite attempts to dismantle the militant network that perpetrated the worst terrorist attack in Paris in generations last November.
In Washington, State Department spokesman John Kirby said U.S. citizens were among the injured, but he would not say how many. No Americans are known to have died in the attacks, although that information may change, he said.
The State Department issued a travel warning late Tuesday, telling Americans they face “potential risks” if they travel in Europe. The warning cited the possibility of further attacks.
In Havana, at the end of a landmark trip, President Barack Obama urged “the world to unite” to fight terrorism, and he pledged to “do whatever is necessary” to aid the investigation in Belgium.
The assaults brought Brussels to a virtual standstill. The subway and airport were both closed — the latter will remain so on Wednesday — and Belgian leaders warned residents to stay indoors. Foreign governments, including Britain, issued travel advisories warning against travel to the Belgian capital.
This report includes material from The Associated Press and The New York Times.