These concerns are entirely justified. Ahmad al-Mohammed and one other of the jihadis who murdered 130 people in Paris in November 2015 had just entered Europe as refugees.

In February 2015, the Islamic State boasted it would soon flood Europe with as many as 500,000 refugees. And the Lebanese Education Minister said in September 2015 that there were 20,000 jihadis among the refugees in camps in his country. Meanwhile, 80% of migrants who have come to Europe claiming to be fleeing the war in Syria aren’t really from Syria at all.

So why are they claiming to be Syrian and streaming into Europe, and now the U.S. as well? An Islamic State operative gave the answer when he boasted in September 2015, shortly after the migrant influx began, that among the flood of refugees, 4,000 Islamic State jihadis had already entered Europe. He explained their purpose: “It’s our dream that there should be a caliphate not only in Syria but in all the world, and we will have it soon, inshallah.” These Muslims were going to Europe in the service of that caliphate: “They are going like refugees,” he said, but they were going with the plan of sowing blood and mayhem on European streets. As he told this to journalists, he smiled and said, “Just wait.”

On May 10, 2016, Patrick Calvar, the head of France’s DGSI internal intelligence agency, said that the Islamic State was using migrant routes through the Balkans to get jihadis into Europe.

“FEARS hundreds of ISIS terrorists could have snuck into Germany,” by Allan Hall, Express, June 10, 2016:

A GERMAN politician is calling for a review of all security procedures in the state housing the most refugees – as fears grow that hundreds of Islamic State (ISIS) terrorists have sneaked into the country disguised as migrants. The security expert of the conservative CDU party in North Rhine-Westphalia called for the review after it was discovered that three of four terror suspects plotting mass carnage in the city of Duesseldorf were all living in refugee camps and had travelled from Syria disguised as refugees. He said it was “naive” to believe statements from members of his own party that no terrorists had inveigled their way into the country disguised as asylum seekers. He said: “Even now we do not know the identity of everyone. “The security authorities in North Rhine-Westphalia have to organise an immediate security review of all refugees living in the state.” North Rhine-Westphalia has Duesseldorf as its capital and Cologne as its biggest city. Dozens of migrant men robbed and sexually molested hundreds of women on New Year’s Eve in Cologne in scenes which forever changed the German perception of refugees. Hans-Georg Maassen, the head of Germany’s internal intelligence agency, had previously said that ISIS did not need to smuggle people into the country in the refugee wave because they had “other means” of launching attacks – including radicalising disaffected converts and Muslims already living in Germany. But the Duesseldorf cell arrests have changed all that. Justice minister Heiko Maas said: “Our investigating authorities must crack down on suspected terrorists with all means available to them under the law.”…

Great idea! Why didn’t anybody think of that before?