BRUSSELS (AP) -- European Union leaders will push ahead Thursday with contested plans to send tens of thousands of migrants back to Turkey amid deep divisions over how to manage Europe's biggest refugee emergency in decades.
With European unity fraying in the face of more than 1 million migrant arrivals over the last year, Turkey — the source of most refugees heading to Greece — is seen as the key partner to contain the influx.
The U.N. refugee agency has reservations about asylum standards in Turkey and rights groups are concerned over Ankara's crackdown on the media and its bloody conflict with Kurdish rebels.
The EU, however, feels it has no better option.
"How are you going to help Greece without having an agreement with Turkey to handle the issue? Do you really want to condemn Greece to become a refugee camp for the rest of Europe?" EU Commission vice president Frans Timmermans said, on the eve of the two-day summit in Brussels.
Destabilized by the passage of hundreds of thousands of migrants, countries in the Balkans have begun to tighten border controls, with Macedonia north of Greece having all but locked the gates. Thousands have been camped on the Greek side desperately hoping to move on toward Germany or Scandinavia.
Under the agreement, which could be sealed with Turkish Prime Minister Ahmet Davutoglu on Friday, Turkey would stop migrants leaving and take back from Greece all "new arrivals" not eligible for asylum.
For every irregular migrant returned, EU countries would take in one Syrian refugee from Turkey, up to a total of about 70,000 refugees resettled in all in a process supervised by the UNHCR, diplomats say.
"This will be a temporary and extraordinary measure which is necessary to end the human suffering and restore public order," says a draft of EU leaders joint statement with Turkey, seen by The Associated Press.
In exchange, the EU could provide Turkey with up to 6 billion euros ($6.6 billion) to help the 2.7 million Syrian refugees there, and speed up EU membership talks and an easing of visa rules for Turkish citizens.
Rights groups fear the deal is a fig-leaf to hide the deportation of migrants, even though the EU insists that each person can make a case in an interview and has the right to appeal.
Changes made to the draft deal since it was made public on March 7 "do little to hide Europe's shameful planned mass return of refugees to Turkey," Amnesty International said Wednesday.
Within the 28-nation EU, several countries are uncomfortable with parts of the agreement.
Cyprus is brandishing a veto if Turkey continues to refuse to recognize the island state. Spain objects to blanket returns.
Hungary has ruled out resettling any refugees from Turkey, claiming that it will only encourage more people to come.
Austria, France and Germany oppose Turkey's membership of the EU. France is constitutionally bound to hold a referendum on its accession. But it may not come to that; in a decade of membership talks Turkey has closed only one of the 35 policy chapters it must complete to join.
Beyond that lie real fears that shutting down Turkey and the Balkans migrant route will only open new ones in places like Albanian and Bulgaria, or that Syrians in Lebanon and Jordan might leave for Turkey, looking to be resettled.
"The catalog of issues to be resolved before we can conclude an agreement is long," EU Council President Donald Tusk wrote in an invitation to leaders on the eve of the summit he will chair.