A leading global medical charity has announced it will no longer accept funds from the European Union or its member states because of the bloc's "shameful" and "damaging" migration policies.
Medecins Sans Frontieres (Doctors Without Borders) said the EU-Turkey deal has left thousands of migrants, including lone children, stranded on Greek islands in "dire conditions".
Under the terms of the agreement, migrants arriving in Greece are meant to be given a swift interview to determine whether they will be allowed to remain or sent back to Turkey.
The EU takes in one Syrian refugee from camps in Turkey for each irregular migrant returned, in a move which is intended to break the business model of people-smugglers who have made fortunes by providing spaces in boats to desperate refugees.
The deal has been thrust to the front and centre of the EU referendum campaign, as Turkey in return won agreement to accelerate visa liberalisation for its 75 million nationals, who could gain visa-free access to the Schengen borderless area - which does not include the UK - as well as the reopening of long-stalled negotiations on its application to join the EU.
Brexit campaigners have raised fears about the immigration implications of Turkey joining the EU but Prime Minister David Cameron has insisted the country's failure to meet the terms of accession means its membership is unlikely to be finalised until the year 3000.
The Leave campaign has also been criticised for stoking prejudice with its warnings about Turks coming to Britain and committing crimes if the country votes to stay in the EU.
And Ukip leader Nigel Farage has been accused of promoting a "racist" Brexit poster showing queues of non-white migrants on the borders of the EU.
MSF said Europe's focus has shifted to keeping migrants out of the continent rather than helping them, warning that the EU-Turkey deal has put at risk the concept of a refugee - defined as someone fleeing war and persecution and entitled to a safe haven.
The charity said 8,000 people, mainly from war-torn Syria, Iraq and Afghanistan, are stranded in Greece as a "direct consequences" of the deal and are living in overcrowded camps, sometimes for months on end, in fear of deportation to Turkey and denied legal aid.
Jerome Oberreit, international secretary general of MSF, said: "For months MSF has spoken out about a shameful European response focused on deterrence rather than providing people with the assistance and protection they need.
"The EU-Turkey deal goes one step further and has placed the very concept of 'refugee' and the protection it offers in danger.
"Is Europe's only offer to refugees that they stay in countries they are desperate to flee? Once again, Europe's main focus is not on how well people will be protected, but on how efficiently they are kept away.
"Europe's attempt to outsource migration control is having a domino effect, with closed borders stretching all the way back to Syria. People increasingly have nowhere to turn.
"Deterrence policies sold to the public as humanitarian solutions have only exacerbated the suffering of people in need. There is nothing remotely humanitarian about these policies. It cannot become the norm and must be challenged.
"MSF will not receive funding from institutions and governments whose policies do so much harm. We are calling on European governments to shift priorities - rather than maximising the number of people they can push back, they must maximise the number they welcome and protect."
The charity said it has been helping people who cross into Europe from the Mediterranean since 2002 and in the last 18 months treated an estimated 200,000 people on the continent and at sea.
The organisation is currently caring for refugees and migrants in Greece, Serbia, France, Italy and on the Mediterranean as well as in countries across Africa, Asia and the Middle East.
In 2015 it received 19 million euros (£15 million) from EU institutions and 37 million euros (£29 million) from member states and has a partnership with the UK alongside eight other EU countries.
The UK Department for International Development does not currently provide any funding to MSF.
The last funding was £1.2 million for humanitarian assistance in the Democratic Republic of Congo in the financial year 2015-16.