BRUSSELS — An Islamic State bombmaker whose DNA connected him to November’s Paris attacks was one of two suicide bombers at Brussels Airport, two intelligence officials said Wednesday, the strongest link yet between two Islamic State attacks that have stunned Europe with their power and planning.
Najim Laachraoui, 24, who is believed to have prepared explosives for the November Paris attacks, blew himself up at Brussels Airport on Tuesday, according to an Arab intelligence official and a European intelligence official, speaking on condition of anonymity to discuss sensitive findings.
Laachraoui, who Belgian prosecutors earlier Wednesday said they still believed was on the loose, joined forces in the suicide attack with Ibrahim el-Bakraoui, 29, a Belgian with an extensive criminal record. A third man who left a bomb in the airport but escaped is still at large, prosecutors said Wednesday. Bakraoui’s younger brother, Khalid el-Bakraoui, 27, carried out a suicide bombing on the Brussels metro 73 minutes after the initial attack at the airport, prosecutors said Wednesday.
The men who brought chaos and carnage to Brussels may have been spurred to act by fears that counterterrorism agents were closing in, according to a message linked to one of the suspected suicide bombers that was described by authorities Wednesday.
The missive, contained in a discarded computer, does not specifically cite recent raids across Belgium, including one that netted a key suspect in last year’s Paris attacks. But its tone suggests a sense that the noose was tightening, according to Belgium’s federal prosecutor, Frederic Van Leeuw.
Fears that authorities were closing in may help explain the involvement of Laachraoui in the suicide bombing at the airport. Terrorism experts regard bombmakers, especially those trained in handling sensitive explosives, as among the most valuable and protected members of a terrorist organization. It is highly unusual for them to participate in suicide attacks themselves.
The computer message also gives apparent insight into the tactics, organization and motivation of the militants who perpetrated the worst attacks on Belgian soil since World War II, and possibly a deeper look into the wider network linked to last year’s Paris massacres.
At least one of the men believed to have been a suicide attacker was deported to Europe from Turkey in July 2015 after Turkey determined he was a militant, Turkish President Recep Tayyip Erdogan said Wednesday. He suggested that counterterrorism officials had the militant on their radar long before the November Paris attacks or Tuesday’s bloodshed in Brussels. Interpol had also issued a “red notice,” effectively an international arrest warrant, for one of the suspects at the request of Belgian authorities.
In the note — discovered on a computer dumped near an apartment containing bombmaking material — one of the suspected suicide attackers, Ibrahim el-Bakraoui, apparently described feeling pressure bearing down.
He wrote that he was “in a hurry, no longer know what to do, being searched for everywhere, no longer secure,” according to Van Leeuw’s description of the message, which was not made public.
Ibrahim el-Bakraoui was identified by authorities as among three suicide bombers who struck Brussels airport and a metro station in back-to-back attacks, killing at least 31 people and injuring 270.
The Islamic State terrorist organization claimed responsibility for the attacks.
Authorities now believe that the bombers had close connections to the Paris attackers.
The same bombmaker may have been involved in both attacks, and Khalid el-Bakraoui is believed to have used an assumed name to rent a Brussels area apartment where Abdeslam’s fingerprints were found last week.
The computer file does not mention Abdeslam by name, but it says the attackers feared that if they did not strike quickly, they risked winding up in prison alongside “him.”
“If they drag on, they risk finishing next to him in a cell,” Van Leeuw said, paraphrasing the content of the file.
Van Leeuw described the file as a “will” discovered on a computer. He did not explain why authorities believed the computer belonged to Ibrahim el-Bakraoui.
Authorities also found large stockpiles of bomb-building materials at his apartment in the Schaerbeek area of Brussels, the prosecutor said: 33 pounds of TATP explosives, nearly 40 gallons of acetone, eight gallons of hydrogen peroxide, detonators and a suitcase full of nails and screws.
Khalid el-Bakraoui, the younger brother, was identified by his DNA in the attack on the subway, the prosecutor said. Ibrahim el-Bakraoui was identified by fingerprints recovered at the scene of the airport blast.
Belgian media initially reported that a suspect arrested Wednesday was Laachraoui, 24. But those reports were later retracted. His DNA was found on at least one bomb used in the Paris attacks.
The latest violence has left European leaders again scrambling for ways to plug holes in security, even though it became increasingly clear Wednesday that at least one of the attackers had repeatedly passed through security nets without being detained by European authorities.
Turkey warned European authorities that one of the suspected suicide bombers was a “foreign terrorist fighter,” Erdogan, the Turkish leader, said Wednesday. A Turkish official cited by the Associated Press later said that the suspect was Ibrahim el-Bakraoui and that in July 2015 he had been deported to the Netherlands at his request. European authorities let him go because they could not establish links to terrorism, Erdogan said.
In Brussels, leaders called for new powers to fight terrorism, although it was unclear whether there would be any progress this time, since similar proposals were made, then rejected, after last year’s attacks in Paris.
French Prime Minister Manuel Valls repeated calls for sweeping new powers to be given to European intelligence agencies, warning that the future of European unity is at stake.
“If the European project is running out of steam, if the populists are gaining in popularity, it’s because a lot of speeches are not followed up in reality,” Valls said Wednesday in Brussels, criticizing the vows for reform that have followed other recent terrorist attacks but yielded few concrete changes.
“In the years to come, the [E.U.] member states will have to invest massively in their security systems,” he said.
In further signs of jitters across Belgium, sports officials called off a soccer match between Belgium and Portugal scheduled for Tuesday in Brussels “because of security concerns.”
Brussels Airport will remain closed at least through Thursday, officials said. At Brussels’s main synagogue, events marking the Purim holiday were called off.
Authorities had been bracing for a possible attack in Belgium for months as the country struggled to stem a tide of homegrown extremism and as the Islamic State repeatedly threatened to hit Europe in its core.
The targets in Brussels — home of the European Union and NATO — also appeared to have been chosen for their symbolic value and for their ease of access.
“What we had feared has happened,” said Belgian Prime Minister Charles Michel. “This is a black moment for our country.”
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, 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 el-Bakraoui 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 luggage 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-filled 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.
In Washington, State Department deputy spokesman Mark Toner said that “approximately a dozen” Americans were injured in the blasts, but that “a number” of U.S. citizens remained unaccounted for on Wednesday — without providing more specific figures.
The State Department also issued an alert on traveling in Europe, urging Americans to avoid crowded places and to exercise caution during religious holidays and at large festivals or events.
Europe has struggled mightily with spillover from the churning conflict in Syria. Thousands of European citizens have traveled there to fight in a war that has become a focal point for jihadists around the world. Many have returned to Europe radicalized. Europe has vowed to confront them.
“This is a kind of scenario every capital in Europe feared since the November attacks last year. A mixture of foreign fighters coming back with experience, local sympathizers on the other hand,” said Rik Coolsaet, a terrorism expert at Ghent University who has advised the Belgian government on how to fight radicalization. “You have such a large number of soft targets, and you cannot secure all of them.”
James McAuley and Anthony Faiola in Brussels, Daniela Deane and Karla Adam in London, and Brian Murphy, Carol Morello and Matt Zapotosky in Washington contributed to this report.