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 in Brussels — home of the European Union and NATO — 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 beneath the modernist glass-and-steel high-rises that house the E.U. erupted in smoke and flame.
Some 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.
The attack at the airport could have been far worse, said Belgium’s federal prosecutor, Frederick Van Leeuw. The biggest bomb — packed inside the suitcase that was wheeled on a cart by the man now being sought by a massive dragnet — failed to go off, he told reporters.
Surveillance camera images show the man, wearing a hat pulled low, next to Ibrahim Bakaouri and another man — still unidentified who is believed to have died in the blasts. All three are walking through the airport departure hall with apparent explosive-packed cases on trolley carts.
Images from a subway station 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