The UN has expressed concern over a radical EU-Turkey plan to ease the migrant crisis, saying it could contravene international law.
Under the plan, all migrants arriving in Greece from Turkey would be returned and for each Syrian sent back, a Syrian in Turkey would be resettled in the EU.
The UN's refugee agency said any collective expulsion of foreigners was "not consistent with European law".
Amnesty International called the plan a death blow to the right to seek asylum.
The deal, discussed at a summit in Brussels on Monday, has not been finalised and talks will continue ahead of an EU meeting on 17-18 March.
Europe is facing its biggest refugee crisis since World War Two. Last year, more than a million people entered the EU illegally by boat, mainly going from Turkey to Greece.
Most of them were Syrian, fleeing the country's civil war. Another 2.7 million Syrian refugees are currently in Turkey. Keep Reading