The dramatic fall of former Syrian president Bashar al-Assad instantly intensified the debate across Europe and the Middle East over the world’s largest pool of refugees, with calls already accelerating for the millions of Syrians who fled their nation’s civil war to begin returning home.

It is possible, observers warned, that host countries could be trading one refugee flow for another if large numbers of Syrians flee a new and unpredictable regime. But for host countries and refugees themselves, the flight of Assad and capture of the capital by Islamist rebels amounted to a game-changing moment in a humanitarian crisis that, through historic waves of asylum seekers, upended societies thousands of miles from Damascus.

On Monday, a growing number of European countries — including Austria, Belgium, Britain, Denmark, Germany, Norway and Sweden — announced that they were suspending the processing of Syrian asylum claims.

In Germany, which absorbed the highest number of Syrian asylum seekers in Europe, and where an anti-refugee backlash has been growing ahead of February’s election, Monday’s announcement meant freezing 47,270 applications. Interior Minister Nancy Faeser said decisions would depend on how the situation unfolds.

“The end of Assad’s tyranny is a great relief for many people who have suffered torture, murder and terror. Many refugees who have found protection in Germany have renewed hope of returning to their Syrian homeland,” she posted on X. But she added:

“The situation in Syria is currently very confusing. Therefore, concrete possibilities for return cannot be predicted at the moment and it would be dubious to speculate about this in such a volatile situation.”

Some host countries went further, suggesting they would be pressing Syrians to leave. Austrian Interior Minister Gerhard Karner said his ministry was preparing a plan for “orderly repatriation and deportation to Syria.”

“As a first step, I would say we make an offer,” Jens Spahn, a senior opposition politician from Germany’s conservative Christian Democrats (CDU), told German breakfast television Monday. “How about if the federal government says: Everyone who wants to return to Syria, we will charter planes for them and they will receive a starting fund of 1,000 euros.”

Even before the Syrian rebels’ stunning advance, a simmering backlash against asylum seekers had provoked once-receptive nations, including Germany and Sweden, to take a hard line on migration and roll back protections. Some conservative European voices, led by Italian Prime Minister Giorgia Meloni, had been pushing for parts of Syria to be declared safe enough for refugee returns. Scenes of jubilation over Assad’s defeat have now accelerated those calls.

Such talk, though, stands in contrast to the European Union’s position on Syria. “The conditions are not met for safe, voluntary, dignified returns to Syria,” E.U. spokesman Anouar El Anouni said Monday.

He noted that the E.U. is “not currently engaging” with the Syrian Islamist group that ousted Assad. The group, Hayat Tahrir al-Sham (HTS), has tried to project itself as more tolerant since breaking ties with Syria’s al-Qaeda branch in 2016, but remains under E.U. sanctions.

“European governments should temper expectations that Syrian refugees will rush back,” said Richard Albright, a former senior U.S. diplomat in the Middle East and Europe specializing in refugees. “The outcome of Arab Spring revolutions in Egypt, Libya and Tunisia will give many pause about uprooting lives they have formed in Europe. Most will want to wait and see how the transition plays out.”

It could take months or longer for clarity on what a new Syria will look like and how hospitable it may be for returnees. Granting them flexibility to come and go without rescinding their protections in host countries could allow them to test the waters, observers argued.

Since the outbreak of the protracted Syrian civil war in 2011, the country’s refugees have spread to 130 nations, according to the United Nations’ refugee agency, with the majority in Turkey, Lebanon, Jordan, Iraq and Egypt, and more than a million spread across Europe.

Some have been eager to return - as they felt the pull of family, faced the difficulty of building new lives in resistant host countries or found themselves in places even more unstable. As Lebanon emerged as the latest battleground in the Middle East, thousands of Syrians had begun streaming back across the border.

But for refugees who have spent more than a decade in the liberal democracies of Europe, returning to a Syria under an Islamist government, even one that has publicly pledged tolerance, could be a jarring change, particularly for children.

Anas Modamani, the Syrian refugee who posed for a viral selfie with German Chancellor Angela Merkel at the height of the crisis in 2015, celebrated Assad’s fall. But the 27-year-old said in an interview that transplants like him now had new lives in new countries.

He has a job as a video editor and camera operator for Germany’s international broadcaster, Deutsche Welle, and lives in Berlin with his Ukrainian fiancée.

“My life is here. Why would I leave my second home behind?” he said. Unlike many of the 1 million Syrian refugees in Germany, however, he also has German citizenship.

In Germany, the “welcome culture” on display in the summer of 2015 is gone. Many communities say they can no longer accommodate Syrian refugees - they don’t have enough housing or space in their classrooms.

So when revelers gathered in cities across Germany on Sunday — waving Syrian flags and setting off fireworks to celebrate Assad’s ousting — far-right politicians began to call for refugees to return home.

“There is no human right to live permanently in a distant country and collect its social benefits,” Jürgen Braun, human rights spokesman for Germany’s far-right Alternative for Germany, wrote in a statement Monday. “The tens of thousands of Syrians cheering on German streets must all return home immediately. Syria is now a safe country of origin.”

Segments of Europe’s ascendant far right had largely backed Assad. Some of its leading voices warned that his downfall now could have unforeseen consequences - including a possible new wave of refugees fleeing whatever new state arises from the Islamist victories. A new wave of asylum seekers ran a heightened risk, some argued, of being infiltrated by the kinds of Islamist militants who’ve masqueraded as migrants before to stage deadly attacks in Europe.

“In a few months, it is possible that we will pay the consequences of this takeover by Islamic fundamentalists through significant migratory flows,” warned Jordan Bardella, president of France’s far-right National Rally. He said the E.U. should “anticipate the risk of a wave of migration, into which Islamist terrorists could slip.”

Syria remains carved up by rival factions. Returning too quickly could not only prove unsafe for returnees, but pose a formidable logistical challenge for any new government. “The question is whether a country like Syrian can handle so many millions coming back,” said Hanne Beirens, director of the Migration Policy Institute Europe.

At the Turkish border on Monday, Ahmed Daaboun waited in line for hours, hoping to cross back into Syria with two of his sons.

One of them, Nasreddin, was born during the government siege of Aleppo. “I remember the sound the plane would make - he would cry,” the father said. They had been bused out of the city in 2016, under a deal to evacuate civilians and rebel fighters. Daaboun said he had been a driver in Aleppo, and in Turkey worked at home with his family making clothing accessories. “A Turkish woman, she got me work, God bless her,” he said.

Life in Turkey had been good, he added. But his house in Aleppo was waiting to be repaired after it was burned, he said, by Assad’s security men. He reckoned that most Syrian refugees in Turkey would similarly seek to return. “After the fall of this regime, there’s no fear,” he said.

Turkey’s Foreign Minister Hakan Fidan, whose country hosts the largest number of Syrian refugees, said Monday that his country would “continue our work to ensure the safe and voluntary return of Syrians and for the country’s reconstruction.”

“It is likely to quite forcefully deport a significant and very large number of Syrian refugees from Turkey,” said Jacob Funk Kirkegaard, senior fellow at the Brussels-based think tank Bruegel. “If that proceeds without blatant violations of human rights, I think countries in Europe, not least Germany, would follow suit.”

Salwan Georges at the Oncupinar border gate in Turkey, Mohamad El Chamaa in Beirut and Stefano Pitrelli in Rome contributed to this report.