Earlier in the day, media outlets reported that at least 875 migrants had arrived in Greece in the last 24 hours despite the EU-Turkey agreement stating that all undocumented migrants who crossed by land or sea from Turkey toward Greece would be automatically returned.
"The lack of clear information being provided to the arriving refugees, and an understanding amongst the humanitarian response actors about the new arrangements, is a major concern," Dan Tyler said.
According to Tyler, another concern is that the refugees continue to arrive but plans for how to receive them and how the so-called hotspots should function are not ready yet.
Under the agreement, the European Union is expected to accelerate Turkey's bid to join the union and introduce a visa-free regime between Turkey and Europe, as well as granting a total of 3 billion euros (over $3.3 billion) to Turkey to help it provide for refugees on its soil. An additional 3 billion euro in assistance to Ankara may be given by 2018.
Europe has been beset by a massive refugee crisis, with hundreds of thousands of undocumented migrants fleeing their home countries in the Middle East and North Africa to escape violence and poverty. Many of them take the West Balkan route, which crosses Greece, using the county as an entry point into the bloc from which they travel onward to wealthier EU states where they intend to apply for asylum.