BRUSSELS (AP) — Rights groups have slammed a two-year deal between the European Union and Turkey that has left thousands of migrants and refugees stranded in increasingly precarious conditions on Greek islands.

Greek and international aid groups, including Amnesty International and Human Rights Watch, have described the deal as a failure by Europe to deal with the refugee issue adequately, saying its consequences are to leave people trapped in often hopeless situations.

The March 2016 deal aimed to halt the flow of tens of thousands of people from Turkey to nearby Greek islands, as they attempted to make their way to more prosperous European countries. It stipulated that those arriving after March 20, 2016 would be held on the islands and returned to Turkey unless they successfully applied for asylum in Greece.