The Turkish president has vowed to unblock what was once considered the main gateway for refugees seeking sanctuary in Europe. Recep Tayyip Erdogan demanded the US and the EU create a safe zone in northern Syria.
Erdogan has urged the US to take further action on establishing a so-called safe zone in northeast Syria, where Washington has a military presence in support of a Kurdish-led force fighting the "Islamic State" militant group.
"This either happens or otherwise we will have to open the gates," said Erdogan. "Either you will provide support, or excuse us, but we are not going to carry this weight alone. We have not been able to get help from the international community, namely the European Union."
The Turkish government has said it intends to settle up to 1 million refugees in northern Syria. But critics say refugees should be resettled in their hometowns.
"Settling hundreds of thousands of Syrians, who are from outside our areas, here would be unacceptable," said Syrian Kurdish official Badran Jia Kurd, referring to northeastern Syria.
Turkey considers Syrian Kurdish fighters near the border a threat to national security. Earlier this year, Erdogan had threatened further incursions into the Kurdish-held area if the US did not take proactive steps to establish a safe zone.
"This looks like an attempt to build pressure for more US concessions on the safe zone, where some refugees could then be resettled for purposes of domestic public relations" by Turkey, said Nicholas Danforth, a senior visiting fellow at the German Marshall Fund.
From escalating violence in the Middle East and Africa to incoherent asylum policy at home - DW looks at how the EU has found itself in the midst of a refugee crisis.
Image: picture-alliance/dpa
Fleeing war and poverty
In late 2014, with the war in Syria approaching its fourth year and Islamic State making gains in the north of the country, the exodus of Syrians intensified. At the same time, others were fleeing violence and poverty in countries such as Iraq, Afghanistan, Eritrea, Somalia, Niger and Kosovo.
Image: picture-alliance/dpa
Seeking refuge over the border
Vast numbers of Syrian refugees had been gathering in border-town camps in neighboring Turkey, Lebanon and Jordan since 2011. By 2015, with the camps full to bursting and residents often unable to find work or educate their children, more and more people decided to seek asylum further afield.
Image: picture-alliance/dpa
A long journey on foot
In 2015 an estimated 1.5 million people made their way on foot from Greece towards western Europe via the "Balkan route". The Schengen Agreement, which allows passport-free travel within much of the EU, was called into question as refugees headed towards the wealthier European nations.
Image: Getty Images/M. Cardy
Desperate sea crossings
Tens of thousands of refugees were also attempting the perilous journey across the Mediterranean on overcrowded boats. In April 2015, 800 people of various nationalities drowned when a boat traveling from Libya capsized off the Italian coast. This was to be just one of many similar tragedies - by the end of the year, nearly 4,000 refugees were reported to have died attempting the crossing.
Image: Reuters/D. Zammit Lupi
Pressure on the borders
Countries along the EU's external border struggled to cope with the sheer number of arrivals. Fences were erected in Hungary, Slovenia, Macedonia and Austria. Asylum laws were tightened and several Schengen area countries introduced temporary border controls.
Image: picture-alliance/epa/B. Mohai
Closing the open door
Critics of German Chancellor Angela Merkel's "open-door" refugee policy claimed it had made the situation worse by encouraging more people to embark on the dangerous journey to Europe. By September 2016, Germany had also introduced temporary checks on its border with Austria.
Image: Reuters/F. Bensch
Striking a deal with Turkey
In early 2016, the EU and Turkey signed an agreement under which refugees arriving in Greece could be sent back to Turkey. The deal has been criticized by human rights groups and came under new strain following a vote by the European Parliament in November to freeze talks on Turkey's potential accession to the EU.
Image: Getty Images/AFP/A. Altan
No end in sight
With anti-immigration sentiment in Europe growing, governments are still struggling to reach a consensus on how to handle the continuing refugee crisis. Attempts to introduce quotas for the distribution of refugees among EU member states have largely failed. Conflicts in the Middle East and elsewhere show no signs coming to an end, and the death toll from refugee sea crossings is on the rise.
In exchange for blocking migrants from crossing into Greece, the EU offered Turkey €6 billion ($6.6 billion) and the chance to speed up EU accession talks. "To date the EU has provided €5.6 billion out of the €6 billion that was agreed," said EU migration spokeswoman Natasha Bertraud.
More than 1 million irregular migrants entered the EU in 2015. Many of them were refugees fleeing war and extreme poverty in the Middle East, Asia and Africa. That year, nearly 900,000 refugees entered Germany to seek sanctuary.