While Europeans worry about those who have gone to Syria to train with ISIS, millions of Syrian children are at risk of becoming terrorist recruits.

According to a 2014 report by UNICEF (the U.N. agency for children), at least 3 million children are displaced in Syria; more than 1.2 million have fled to neighboring countries. They have been bombed and shelled, seen family members slaughtered, and are forced to live in camps or abandoned buildings. Half no longer have any schooling.

“Syria is the greatest refugee crisis of our times, and children are the most visible victims,” Oubai Shahbander, a former U.S. Department of Defense analyst, said last week at a conference on Syria cosponsored by the New America Foundation. “ISIS is absolutely trying to take advantage of the situation,” he added. “It sees the children as potential recruits.”

Yet there has been far too little attention paid by Western governments to this lost generation of Syrian children. This neglect has moral and strategic implications. Unless something is done to help, these children will supply the next generation of jihadis that threatens the Arab world and beyond.

Syria once had a good education system, but a fifth of its schools have been destroyed, damaged, turned into shelters, or seized by armed militias. Drowning in Syrian refugees, the neighboring countries of Lebanon, Iraq, and Jordan can educate only a fraction of the Syrian newcomers. So these children are growing up with no schooling and no prospects.

“In the camps, they are poor, cold, uneducated, without work, without hope,” said Farah Atassi of the National Syrian Women’s Association. “What do you expect? This is a breeding ground for terror.”

Indeed, ISIS is already sending many young boys to terrorist training camps in areas of Syria it controls. And schools in those regions now inculcate radical Islam.

In other parts of Syria, UNICEF reports, at least a million children live in areas under siege (mostly by regime forces) or in areas of intense fighting. Boys as young as 12 have been recruited, or forced to support the combatants, while many have been arrested and tortured by the Assad government. As these youths mature, they will know little but how to fight.

Moreover, the Assad regime continues to create more refugees by dropping barrel bombs on populated areas, deliberately targeting clinics, bakeries, and any remaining schools. International aid groups can’t keep up.

The regime uses mass displacement of the urban population in rebel-held areas as a strategy, according to Shahbander. “This leaves others to fill the vacuum in places where people can’t leave,” he added. “Nusra (the al-Qaeda group) and Daesh (ISIS) fill it.”

These jihadi groups offer desperate, besieged, or displaced Syrians the services the regime has destroyed.

If there were some prospect of ending this terrible war, the lost generation of Syrian children might still have a future. But the Obama administration is basing its Syria policy on the hope that Assad’s Russian and Iranian backers will godfather viable Syrian peace talks. However, Moscow and Tehran think Assad is winning and show no interest in a compromise solution.

In reality, the war is stalemated. Until the balance tips against him, Assad will drop more barrel bombs, and more Syrians will be forced to flee.

As Shahbander points out, this unprecedented humanitarian crisis has critical security dimensions. Western nations would prefer not to confront these issues, but they will soon have no choice.

The exodus of 3 million refugees from Syria is destabilizing Lebanon, Syria and Jordan. Lebanon, for example, whose population numbers 4 million, has taken in 1.2 million refugees, and more are desperate to enter. That would be the equivalent of 95 million refugees entering the United States.

So the displaced — and their children — will remain in camps, mosques, and schools, bitter and angry at a world that won’t or can’t stop Assad’s war crimes against civilians. And — pay attention to this — experts working with the refugees say they increasingly blame the United States and Europe for their plight.

Why? Because, although the United States and its allies are bombing ISIS in Syria, they won’t hit regime targets or force Assad to stop dropping barrel bombs. Nor is the administration willing to police a no-fly zone in the north, where the refugees can find safety.

Many refugees conclude from this the United States is secretly supporting Assad and his Shiite Iranian backers. That reasoning is bolstered when Secretary of State John Kerry says he’d welcome Tehran’s help in solving the Syrian crisis.

The international failure to end the Syrian war — or prevent Assad from creating more refugees — guarantees a huge source of recruitment for tomorrow’s jihadi movements: a lost generation of children who blame the West for their suffering. The refugees and displaced Syrians “can become an incubator for radicalism, a real danger to the security of our region and ultimately to the United States and its allies,” says Shahbander.

The White House desperately wants to avoid further involvement in Syria beyond humanitarian aid and limited strikes on ISIS. But it can’t afford to allow Syria’s lost generation to morph into a long-term security threat.

Trudy Rubin is a columnist for the Philadelphia Inquirer.