EISENHÜTTENSTADT, Germany — Angela Merkel thought she had regained control over Germany's borders. Turns out the problem might have just shifted.

The German chancellor's decision to open up the country to refugees led to wave after wave arriving through the so-called Western Balkans route into the south of Germany. That route's now all-but closed but official statistics, and local law enforcement, suggest Merkel now needs to look east, to the border with Poland, where the number of illegal crossings has skyrocketed. That is putting pressure on the police and raising concerns about radical Islamists slipping through the cracks.

“The security situation at the German–Polish border is serious,” said Ernst Walter, head of Germany’s federal police union. “Day by day, there could be hundreds or thousands of illegal border crossings into Germany from Poland, with potential terrorists among them — and we simply have no idea about what’s happening.”

Many of those coming are asylum seekers from Chechnya, a predominately Muslim republic where separatists have fought several bloody wars against Russia, and some law enforcement officials worry they don't have enough resources to investigate the migrants' backgrounds, given that there are not enough translators and that reliable information from Chechnya and Russia can be hard to obtain.

Many Chechens enter Germany by car via a highway linking Warsaw and Berlin, named the “Autobahn of Freedom” in honor of the 25th anniversary of the fall of the Iron Curtain.

Largely unreported on by the media or remarked on by politicians, this migrant flow into Germany from the east has solidified over the last year, with people traveling by train from Belarus and entering the Schengen area in the Polish city of Terespol where they can file an application for asylum.

“We have no idea if they stay in Germany or if they travel on to other countries,” a federal police official said. “We simply have no idea.”

Since the German border with Poland is open under the Schengen agreement, there are no official statistics on how many have crossed into the country this way. But nationwide, the number of Russians seeking asylum in Germany grew six fold this year alone, jumping from 307 in January to 1,835 in June, according to Germany's Federal Office for Migration.

A massive backlog means it takes several months for asylum applications to be processed, so these numbers suggest the number of Russian asylum seekers increased at the same time as the spike in refugees from Syria and the wider Middle East.

More recent numbers from the Brandenburg state interior ministry on asylum registrations, which are processed within days of asylum seekers entering the country, suggest that this trend continued into the summer of 2016.

Fleeing repression

Human rights activists say a lack of political freedom and brutal repression of dissidents in Chechnya is what's driving the increase in migration. And while federal officials don't collect records of how many of the migrants say they come from the Chechen republic, local officials say it's the majority.

“Most of these people declared in questionnaires that they came from the Caucasus, especially Chechnya,” said Susann Fischer, a spokesperson at the Brandenburg state interior ministry.

Frank Nürnberger, head of the Brandenburg central registration office for foreigners, recalled a similar surge in 2013. After a dip at the end of 2014, the number started to rise again last year, he said.

“However, no one really took notice because there were so many more refugees coming on the Western Balkans route," said Nürnberger, whose office in the city of Eisenhüttenstadt at the Polish border is one of the main reception centers in Germany for Russian asylum seekers. "The Chechens disappeared in that huge mass [even though] their numbers continued to go up.”

Unlike Germany, Poland does collect statistics on how many Chechens are seeking asylum. Of the almost 8,000 Russians who applied for asylum in Poland last year, 92 percent said they came from Chechnya, according to the Polish interior ministry. So far this year, more than 6,100 Russians have already applied for asylum, 94 percent of them Chechen.

Many Chechens enter Germany by car via a highway linking Warsaw and Berlin, named the “Autobahn of Freedom” in honor of the 25th anniversary of the fall of the Iron Curtain.

“The majority travel on to places like Belgium, France, Germany or Austria, which are seen to be more secure and where there is already a sizable diaspora of Chechens," said Ekaterina Sokirianskaia, project director for Russia and the North Caucasus with the International Crisis Group.

Border controls between Germany and Poland were abolished in 2007. But police can still check travelers at or near the border, though such checks have effectively become impossible due to staffing problems as many officers were reallocated to the Austrian border or major airports, officials said.

A senior police officer, who spoke on condition of anonymity, said that a 90-kilometer area near the German-Polish border was often patrolled by two officers in one car.

A high-ranking German security official dismissed that claim, blaming it on “exaggerated union demands,” though he echoed concern about the migration flow across the German–Polish border.

Back and forth

Under the EU's Dublin agreement, if German officials determine that someone seeking asylum in Germany had entered Poland first — which is the case for most Chechens — the migrants have to be sent back to Poland to complete the asylum application process.

Such returns are often pointless, said Nürnberger.

“To put it in simple terms: People are being brought back to Poland and an hour later they can literally walk back to Germany across the pedestrian bridge connecting Germany and Poland in Frankfurt.”

Nürnberger recalled the case of one Chechen who had threatened employees at a refugee center when he was deported to Poland. Two days later, the Chechen was back at the refugee center, being celebrated by some of his countrymen. “Of course, this leads to frustration among our employees here,” Nürnberger said.

German authorities are concerned about Chechnya as a breeding ground for Islamist terrorists.

The anecdote encapsulates the dilemma faced by Merkel: While there is growing domestic pressure for more security measures, stricter border controls within the Schengen area could cost the country €10 billion a year.

More than 1 million people arrived in Germany to seek asylum last year and the country used an emergency clause in the Schengen treaty to introduce checks at its land border with Austria in September. Austria, France, Denmark, Sweden and Norway also introduced temporary border controls, which are currently limited to a maximum of six months.

Recent polls show that support for Merkel’s refugee policy has plummeted as the country has grown more fearful of terrorism, following a string of attacks this summer, two of which were committed by asylum seekers.

While there has not been any terrorist attack in Germany committed by Chechens, German authorities are concerned about Chechnya as a breeding ground for Islamist terrorists.

According to the interior ministry in Brandenburg, security officials are monitoring 80 people in the state suspected of sympathizing with Islamist terrorism. Many are from the Northern Caucasus and support or sympathize with Islamic State, said ministry spokesperson Susann Fischer.

“Islamic State is actively recruiting ultra-radical Salafists from Chechnya,” said Sokirianskaia from the International Crisis Group. But, she added, the regime in Chechnya brutally cracks down on even non-violent Salafism, seeing it "as a symbol of opposition."

Accordingly, many Salafists feel compelled to leave Chechnya. Most, however, choose destinations other than Western Europe and instead settle in Muslim countries or, in the case of the most radical, decide to fight in Syria, she said.

In late 2013, the state of Brandenburg organized a workshop to inform state officials about potential security threats in connection with the spike of Chechens entering the country.

“Maybe they didn’t share everything they knew with us,” one participant said. “But it seemed like they knew little to nothing about who is coming, what their reasons were, or what the situation was like in Chechnya.”