They’re enemy combatants, adherents of an entity that is waging war against European states. Thus they should not be allowed to return, and every effort should be made to block them from doing so. But apparently such steps would be “Islamophobic.”

“E.U. authorities brace for wave of Islamic State fighters after Mosul assault,” by Michael Birnbaum, Washington Post, October 23, 2016:

BRUSSELS — A long-awaited offensive this week to dislodge the Islamic State from its stronghold city of Mosul is fueling fears of renewed terrorist attacks, as European counterterrorism officials say more fighters are returning home after waging jihad in Syria and Iraq.

The security concerns are a major focus of European intelligence agencies as the Iraqi army and its partners press the assault on Mosul, which the Islamic State has used as a capital for planning and operations for more than two years. Attacks in Paris and Brussels in recent years have been conducted by locally born attackers who in some cases trained with the Islamic State in Iraq and Syria, then returned home.

The threat underlines a central dilemma facing leaders of nations where the Islamic State has carried out terrorist attacks: Even as they support efforts to defeat the group on the ground, they risk dislodging its adherents and casting them elsewhere. Top officials say that they are raising their vigilance as thousands of people stream out of Mosul, which is under heavy bombardment in the largest operation for Iraqi security forces since they were formed after toppling Saddam Hussein.

Counterterrorism officials say it is too early to know whether the Mosul operation will spark a new wave of fighters coming back to Europe. But they say that when the Islamic State has been dealt battlefield blows in the past year, more of its adherents have returned home.

“Further military losses, further military pressure on them in the region, indeed might lead to an increased reflex response by the group in Europe,” said Rob Wainwright, the head of Europol, the Pan-European policing agency that is coordinating efforts to combat the group inside European Union borders. Flows of returning fighters have “slightly increased” in recent months, he said. “Not yet in high numbers. Maybe Mosul and Raqqa could change that,” he said, referring to the Islamic State’s Syrian stronghold, which is the next major target after Mosul.

Between 4,000 and 5,000 European residents are estimated to have gone to Syria and Iraq to take part in the fight, which has raged since Arab Spring protests in Syria in 2011. A majority of the European fighters are said to be on the ground there, Wainwright said. About a third is estimated to have returned, with the remainder killed.

The trip has been made harder by Turkey’s sealing of its border with Syria, a step that has significantly cut down on traffic in both directions. Turkish officials have said in recent days that they view fleeing Islamic State fighters as a significant domestic threat and that they are committed to bolstering security along the long border with Syria and Iraq. The Islamic State also has been known to kill disillusioned fighters who try to abandon the fight, further reducing return movement.

The group may also seek to pull off high-profile attacks as a way of proving its continued relevance. The flow of new European recruits to the fight has slowed to a trickle this year after posing a major challenge to authorities in recent years.

Still, some movement is possible, Wainwright said.

“ISIL are in the business of getting their people back into Europe in increasingly sophisticated ways,” he said, including paying organized crime groups for high-quality fake travel documents. In recent months, there has been “some pickup in the rate of return,” most noticeably to Britain, Sweden and Italy, he said.

E.U. counterterrorism officials have been warning for months that a string of setbacks for the Islamic State inside the territory it controls could create a threat as its supporters flee and as its leaders seek to prove their ongoing relevance. Repeated attacks on Paris last year, then the March attacks in Brussels, were the first warning sign of the group’s new focus on Europe. Then this summer, a spate of Islamic State-inspired attacks that began on Bastille Day in Nice, France, showed just how little resources were necessary to perpetrate large-scale killings.

“We have to be prepared, that’s the point. It’s a lot of people,” E.U. Counterterrorism Coordinator Gilles de Kerchove said. “We don’t know whether it will be a massive return or whether it will be over a long period of time.”…