CEUTA, Spain—Obaid Aleilmi woke up on a recent afternoon, after working the night shift, to a flood of messages on his phone saying the border was open.
He didn’t think long. Hours later, the 25-year-old university student was hopping onto the back of a truck full of other young men, headed for the Spanish territory of Ceuta.
He joined some 72,000 people who climbed over fences and swam around a breakwater to get into Ceuta, spreading panic in the tiny territory and exposing the vulnerability of Spain’s border with Morocco. Videos of the migrants streaming across the border went viral and evoked memories of Europe’s 2015 migration crisis.
The flood of migrants also sparked questions about they could have crossed the border in such enormous numbers. Never before had so many people forced their way into the exclave in so little time.
For days, theories have circulated online about what might be behind it. Was it the Moroccans trying to get political leverage over Spain? Maybe it was the Russians trying to destabilize Europe? Perhaps it was the Americans trying to retaliate against Prime Minister Pedro Sánchez for becoming one of the Trump administration’s chief antagonists in Europe? Or was it the Israelis punishing Sánchez for his vocal criticism of the war in Gaza?
Spanish authorities are still investigating what happened, but they have so far come to a far more pedestrian conclusion. The working hypothesis of Spanish intelligence is that the mobilization was spontaneous and spurred on by social media, rather than orchestrated by Morocco or any other country, according to a senior Spanish security official.
The Moroccan government said it had nothing to do with the sudden mass influx of people into Ceuta. It blamed human traffickers, and said they had strengthened, not eased, security measures in response to the mass movement of people toward the Ceuta border. The Spanish government has also blamed human traffickers, rather than the Moroccan government.
At least one cause was clear: deep social and economic discontent among Morocco’s Gen Z. Thousands dropped everything to gamble on a chance for a better life in Europe.
A court ruling
Ceuta, like its sister city Melilla, are geographical oddities. They are in North Africa but they have belonged to Spain for centuries.
Those traveling from the territories are subjected to special border checks—meaning immigrants can’t freely travel from them to continental Europe. Under a longstanding arrangement with Morocco, Spain can immediately expel people who enter its exclaves illegally, a practice known in Spanish as devoluciones en caliente, or “hot returns.”
A ruling published July 8 by Spain’s Supreme Court made it harder for individuals who reach Ceuta by sea to be immediately expelled. The ruling was based on a technicality: The “hot return” procedure applies to people who force their way through physical barriers, and the court concluded that the sea didn’t meet that definition. The court said that people who reached the territories by sea first had to be individually processed.
Many Moroccans who joined the wave of migrants appear to have seized on a misinterpretation of the ruling. Facebook and Telegram posts repeated a phrase that appeared in a headline of a local news report: Those who swim to Ceuta or Melilla “cannot be returned.”
Early warnings
In Morocco, Aleilmi was studying business and working part time as a waiter, earning 1 euro an hour. He felt Morocco offered no opportunities to young, educated people like him. His two older siblings have university degrees and both are still unemployed. Europe was tantalizingly close. If only he could make it to the other side of the border, he thought.
“To be honest, it wasn’t really a choice, the reality and living conditions in Morocco forced me on this path,” he said. Tens of thousands of young Moroccans felt the same
By mid-July, small groups of people, mostly Moroccans, were attempting to swim to Ceuta daily. The Moroccan navy deployed additional vessels to stop them. Some 50 people were intercepted on July 12 alone, according to state media.
Many still made it through, planning their crossings with waterproof bags for phones, cash and other essentials.
Spanish intelligence informed Sánchez’s government that the Supreme Court ruling was causing problems, with 200,000 people actively exploring the possibility of heading to Ceuta, according to a Spanish official. It warned of a possible wave of arrivals on the occasion of Throne Day, which marks the anniversary of King Mohammed VI’s accession to the throne.
Yet, little was done to strengthen the border. The breakwater that separates Ceuta from Morocco, long regarded as ineffective, was left just as it was.
“We have demanded more agents and more resources for many years,” said Rachid Sbihi, the spokesman for the trade union representing the civilian police force in Ceuta. “Politicians don’t listen.”
Throne Day
A video published in Spanish media on July 28 showed two young Moroccan women in wetsuits celebrating their arrival in Ceuta. It went viral, as did other videos of successful crossings. “Viva Pedro Sánchez!” wrote one of the commenters. Online discussions about reaching Ceuta intensified.
“There was a deliberate digital campaign, spreading via WhatsApp and Facebook groups, that coordinated meeting points and crossing instructions,” said Ruslan Trad, a nonresident fellow at the Atlantic Council’s Digital Forensic Research Lab. Smugglers played a role, but the inaction of Moroccan forces was an even bigger factor, he said.
The head of Ceuta’s local government, Juan Vivas, raised the alarm about the emerging crisis, saying there were some 200 crossings daily and that arrivals had reached 1,500 by July 29.
In Morocco, July 30 was Throne Day, a public holiday. Moroccan security forces were assigned to other duties and neglected border control, according to the senior Spanish security official. Many were free to try their luck, jumping on trucks, buses and motorbikes to reach Ceuta.
Hungry in Ceuta
Those who made it to Ceuta initially celebrated, shouting “Viva España.” Reality soon hit. The migrants struggled to find water or food, let alone shelter. Most shops shut for fear of looting.
Meanwhile, the Spanish government deployed the army and additional Civil Guard troops, as well as divers and boats to patrol the sea. Spanish authorities laid a 500-yard inflatable barrier that extends from the breakwater to discourage arrivals and address the legal loophole raised by the Supreme Court. Morocco beefed up security on its side of the border.
Many migrants left voluntarily. Others were rounded up by Spanish forces and escorted to the border. By Saturday, most of migrants had returned to Morocco. Several thousand remain in Ceuta, including minors who cannot be immediately returned.
Aleilmi, the student, is also still there. He has spent much of the past week hiding in the thick pine forest of the hills overlooking the city. He says he is running out of money, but he is determined to make it to Europe.
“It’s the only way I can secure a stable and comfortable future for myself and my family,” said Aleilmi.
Write to Benoit Faucon at benoit.faucon@wsj.com and Margherita Stancati at margherita.stancati@wsj.com