Schengen took a wrong turn during a recent flight from Greece to Germany. Berlin decided to block free travel within the Schengen zone in response to Europe’s refugee crisis and Islamic terror.

The Schengen agreement abolished border controls between most European Union member states in 1985, allowing for passport-free travel.

As reported by Deutsche Welle (DW), Germany’s interior ministry says the measures were enforced earlier this month after authorities there counted more than 1,000 illegal entries from Greece since the start of the year. They said security measures across the board were being beefed up amid fears of a terror attack during the holiday season.

Athens complained to Berlin. But the security concerns are not only limited to Germany, according to DW.

Just days before Germany enforced the new travel regulations, British agents helped Greek police smash a major Athens-based smuggling gang that operated four forgery laboratories, selling fake passports and work papers to migrants bound for the UK. Other clandestine operations have been busted throughout the year for smuggling thousands of illegal migrants from the Middle East to Italy, Spain and Germany.

Last year, France offered to dispatch a special task force to Greece to assist in the identification of fake documents found in the hands of thousands of illegal migrants. But the Greek government refused the request, steering the EU’s attention to Turkey to block the inflow of illegal refugees and migrants.