(Bloomberg) -- German Chancellor Angela Merkel’s government is watching with alarm the growing number of migrants reaching the Greek islands from Turkey.

The swell of asylum seekers crossing the western Aegean Sea is a sign of trouble in the arrangements hashed out with Turkey that eventually staunched the flow of arrivals during the crisis of 2015 and 2016. A new influx, even if nowhere near the same scale, has the potential to stir up trouble for Merkel who suffered from the populist backlash against her open-door policy, according to a German official who spoke on condition of anonymity.

In contrast with public statements offering a more measured take, security authorities studying the migration patterns in Berlin are beginning to alert their leaders to the risk, the official said.

“We’re looking at it with concern,” German Foreign Minister Heiko Maas told reporters in Berlin on Thursday, adding that he’d spoken with his Turkish counterpart this week. “It was a constructive discussion and so I expect that the situation will normalize step by step.”

The up-tick goes beyond the usual summer increase and has officials pointing to Turkey, which pledged to halt the flow of migrants in return for 6 billion euros ($6.6 billion) in aid from the European Union.

Turkey’s Threat

With unemployment rising, inflation eating into wages, and almost 4 million refugees already from the civil war in Syria, Turkish President Recep Tayyip Erdogan is now confronted with a fresh wave of people fleeing Syria’s northwestern province of Idlib, the last remaining rebel bastion. Erdogan is threatening to channel more migrants into Europe if the EU doesn’t do more to help.

“We may have to open the doors,” Erdogan told lawmakers of his Justice and Development Party in Ankara on Sept. 5. “Are we going to carry this burden alone? We could not receive the necessary support in sharing the burden of the refugees primarily from the EU and the world.”

Migration to Europe has dropped off dramatically since more than a million asylum seekers entered the bloc four years ago, above all to Germany. But the influx redrew the EU’s political map, driving a wedge between member states and fueling a rise in far-right populism that exploited social anxiety in the aftermath of the financial crisis.

Populists Profit

In Germany, the hardening of social tensions has been palpable. A fatal stabbing by a suspected asylum seeker last year in Chemnitz in the country’s east plunged the city of 247,000 into rival demonstrations and unrest for days.

The political beneficiary has been Alternative for Germany, or AfD, which secured a vocal following when it started out by decrying euro-crisis bailout policy. After 2015, the party won a new lease of life -- and shifted to the political extreme -- as it hammered away at Merkel for not shutting Germany’s borders to migrants. The AfD, as it’s known, won 27.5% of the vote in the eastern German state of Saxony in a Sept. 1 regional vote, second to Merkel’s Christian Democratic Union.

It wouldn’t require numbers on the order of the 2015 crisis to spark fresh political upheaval, according to the German official. Merkel’s chief spokesman, Steffen Seibert, said the government was watching the migration flows “very closely.”

“The recent increase in arrivals must be taken seriously, but the figures are on an order of magnitude lower than before the EU-Turkey accord,” Seibert told reporters in Berlin on Wednesday.

Greek Appeal

Refugee arrivals to islands of the western Aegean, including Lesbos, Chios and Kos, have more than doubled compared to last year, according to a spokesman at Greece’s Citizen Protection Ministry. Shelters on the islands recorded a 58% increase in the number of refugees to 24,735 by the end of August compared with the end of May, ministry data showed. That compares to a 14% increase in the year-earlier period.

The government in Athens, which took office just two months ago, is looking to both Brussels and Ankara for support, wary of getting left to tackle the problem alone.

Georgios Koumoutsakos, deputy citizen protection minister, on Thursday briefed ambassadors from EU member states on the latest developments in the Greek capital.

The movements were “definitely not just Greek, but mainly European -- and should be dealt with as such,” Koumoutsakos said in an emailed statement. “All involved parties must actively take on their responsibilities.”

--With assistance from Selcan Hacaoglu.

To contact the reporters on this story: Patrick Donahue in Berlin at pdonahue1@bloomberg.net;Eleni Chrepa in Athens at echrepa@bloomberg.net

To contact the editors responsible for this story: Ben Sills at bsills@bloomberg.net, Steve Geimann

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