Refugee and rights groups have raised serious concerns about a European Union plan to stem the migration crisis, as Greece and Turkey rush to be ready to launch a controversial refugee "swap" programme on Monday.
Officials in Athens and Brussels say that about 500 migrants are due to be sent back from a Greek island to Turkey on Monday, as the EU seeks to close a Mediterranean route that more than one million migrants took to Europe last year.
Greece and Turkey were rushing through legislation on Friday to underpin the scheme, even as the United Nations refugee agency (UNHCR) and Amnesty International cast grave doubt on a plan that leading rights groups call unethical and possibly illegal.
"UNHCR is today urging parties to the recent EU-Turkey agreement on refugees and migrants to ensure all safeguards are in place before any returns begin. This is in light of continued serious gaps in both countries," said Melissa Fleming, a spokeswoman for the UN group.
Under the EU-Turkey plan, any migrant who does not qualify for or does not seek asylum in Greece will be returned to Turkey, and in return a Syrian refugee from one of many Turkish camps will be sent to the EU.
But hundreds of staff that EU states pledged to send to Greece to implement the process are yet to arrive, raising the danger that not all asylum cases will be assessed individually, which is a key element of refugee law.
“Across Greece, which has been compelled to host people because of closed borders elsewhere in Europe, numerous aspects of the systems for receiving and dealing with people who may need international protection are still either not working or absent,” said Ms Fleming.
She also warned that deteriorating conditions, overcrowding, lack of information and mounting fear at migrants’ camps around Greece created a real danger of “panic and injury” at these sites in the coming days.
Reports of fights among migrants are increasing at Greek camps; on the island of Chios on Thursday night, three people suffered stab wounds during rioting, and dozens of people broke out of the camp on Friday.
It is still not clear how and by whom migrants will be removed from Greece and taken back across the Mediterranean to Turkey, but Turkish prime minister Ahmet Davutoglu insisted the scheme would begin as planned on Monday.
Amnesty said on Friday it was not safe for the EU to send people back to Turkey, where the group's research suggests that the authorities had forcibly returned thousands of Syrians to their war-ravaged homeland in recent weeks – a claim Ankara denies.
John Dalhuisen, Amnesty's director for Europe and central Asia, said that "if the agreement proceeds as planned, there is a very real risk that some of those the EU sends back to Turkey will suffer the same fate."
“It is a deal that can only be implemented with the hardest of hearts and a blithe disregard for international law,” he added.