A militant Islamist fighter filming his fellow fighters taking part in a military parade along the streets of Syria's northern Raqqa province in 2014. REUTERS/Stringer The Islamic State militant group has recently released a barrage of propaganda videos targeting refugees and telling them to come join the "caliphate" instead of fleeing to "xenophobic" Europe.

The videos seek to reinforce the image of the caliphate — the territory ISIS controls in Iraq and Syria — as an Islamic utopia and capitalize on the dangers refugees face as they flee to European countries.

And these videos aren't the first propaganda messages ISIS has released about the refugee crisis — earlier this month, in its English-language magazine Dabiq, the extremist group published an article warning against leaving the caliphate for Western countries.

The articles said leaving for Western nations was "a dangerous major sin" that was "a gate towards one's children and grandchildren abandoning Islam for Christianity, atheism, or liberalism."

This propaganda effort could be a sign of panic in the ranks of ISIS leadership as Iraqis and Syrians flee their home countries in large numbers.

"They claim to create this Islamic utopia, and Muslims are fleeing in droves," Daveed Gartenstein-Ross, a counterterrorism analyst at the Foundation for Defense of Democracies, told Business Insider.

"A legitimate caliphate … is supposed to be able to provide services to its citizens."

ISIS relies on residents in the territory it controls for revenue — it makes most of its money from taxing and extorting residents of the caliphate — and for services that give ISIS-held territories the appearance of being ruled by a functioning government.

"Taxation certainly would [be] an issue with people fleeing," Gartenstein-Ross said. "Another significant problem is brain drain … The people who have highly desirable skill sets like doctors are fleeing."

A map from August showing oil wells under ISIS control. Twitter/@Karybdamoid

Oil is another major source of funding for ISIS, which brought in an estimated $100 million in 2014 from selling crude on the black market.

"The oil industry ... is another area where they haven't preserved the level of talent that they need," Gartenstein-Ross added.

Aside from a possible brain drain and loss of revenue if there are fewer people to tax as ISIS continues its attempt to seize territory across Iraq and Syria, the refugee exodus from the Middle East could call ISIS' legitimacy into question, Gartenstein-Ross said.

And ISIS has a strategy to keep people from leaving the caliphate. The International Institute for Strategic Studies reported recently: "It is in ISIS's interest to prevent a mass exodus by residents living in territory it controls, because this would undermine its image of a cohesive state-building project. The group has accordingly placed IEDs around entrances to cities it controls, such as Fallujah and Ramadi, to prevent escape, which simultaneously serve the larger purpose of preventing the [Iraqi Security Forces] from advancing."

The strategic security firm The Soufan Group noted last week that "more people are visibly fleeing [ISIS] and the areas it controls than are flocking to join it."

"In an attempt to change the minds of people who would rather risk drowning than live in the Islamic State, the group has ramped up its propaganda efforts," The Soufan Group said. "The scatter-shot nature of the Islamic State's recent messages — at times angry and denouncing refugees, at other times proclaiming the wisdom of staying in what the group sees as an Earthly paradise — shows the desperation of a group that resembles a pyramid scheme more than a government."

An ISIS militant next to residents who are holding pieces of wreckage from a Syrian warplane that crashed in Raqqa, in northeast Syria, in 2014. REUTERS/Stringer

Some experts, however, disagree with the characterization of ISIS' media blitz as a sign of desperation or panic.

"I wouldn’t see it as a desperate call for the refugees … because they need people [in their caliphate] but more as a sophisticated move by the Islamic State to take advantage of the huge debate on the refugee movement in Europe," Pieter Nanninga, an assistant professor of Middle Eastern Studies at the University of Groningen in the Netherlands, told Business Insider.

His research focuses on jihadist violence and media use, and he viewed the new videos ISIS posted about the refugee crisis.

New #IS video from wilayat Homs emphasises the humiliation of refugees in Europe, welcomes them to the Islamic State pic.twitter.com/mgpjlnKNRj — Pieter Nanninga (@pieternanninga) September 17, 2015

#IS' 10th refugee video "He will replace you with another people" [Q47:38] contrasts refugees Europe with migrants IS pic.twitter.com/dnNmNTTjyW — Pieter Nanninga (@pieternanninga) September 18, 2015

#pt The video also criticizes the West: they cry for #AlanKurdi, but have neglected Assad's victims in #Syria pic.twitter.com/IlS5rsQ5BE — Pieter Nanninga (@pieternanninga) September 18, 2015

J.M. Berger, a Brookings Institution fellow and coauthor of the recent book "ISIS: The State of Terror," echoed this view.

"I think there are some signs on social media that ISIS is concerned with the refugee flows, but it's possible the leadership's interest is opportunistic," he told Business Insider via email. "The rising xenophobia on display at the moment plays very well into their narrative."

Nanninga sees the Arabic-language videos as a deliberate media campaign seeking to get ISIS supporters and sympathizers to promote ISIS' message of utopia in the caliphate.

"The refugees themselves … I doubt whether they see these videos, I think they will be seen by the supporters of the Islamic State who share these videos on Twitter," Nanninga said.

Hungarian police officers detaining migrants on the tracks at the railway station in the town of Bicske, Hungary, on September 3. Laszlo Balogh/Reuters The videos use footage of a Hungarian camerawoman who kicked a refugee and images of riots on the Hungarian border to show the dangers of traveling to Europe. These images are juxtaposed with footage of food markets and children happily playing in the caliphate.

Nanninga also said the volume of media ISIS had released on the refugee crisis hinted that the propaganda was a calculated, sophisticated move to capitalize on the debate surrounding the refugee movement in Europe.

"It’s remarkable that ISIS has launched 10 videos in a bit more than one day — it's quite unusual," he said. "The message is quite coherent, so it's really an orchestrated campaign from different regions in the caliphate."

Also of note is the fact that most of the refugees streaming into Europe are thought to be fleeing the regime of Syrian President Bashar Assad, who has used barrel bombs on civilian areas, rather than ISIS specifically.

A human-smuggler in Istanbul told BuzzFeed that Assad's war was "about the only reason for the refugees," guessing that about 90% of the Syrian refugees he smuggled into Europe were fleeing Assad.

But this may not negate the idea that ISIS could be worried about the caliphate losing its appeal among Syrians and Iraqis.

"If you look at the areas that we consider Assad-controlled territories, a lot of them are actually where the bulk of the fighting is occurring," Gartenstein-Ross said. "If so, the thing they're fleeing most is war.

"It's the areas that are most disputed where the refugees are coming from … It's the same patterns you see in any war that has ever occurred. There are still massive amounts of refugees from territory ISIS has taken control of."