Greece illegally deported nearly 60,000 migrants to Turkey between 2018 and 2019, a report says.
Turkish Interior Ministry files suggest Greece illegally transported 58,283 people to Turkey in the 12 months to November 1, the German magazine Der Spiegel reported.
Most of the cases registered were Pakistani nationals (16,435), followed by Afghans, Somalis, Bangladeshis and Algerians. There were also more than 4,500 Syrians, the report said.
The documents, which have not been independently verified, said that Greece sent more than 6,500 migrants to Turkey last month.
Turkey has repeatedly accused Greece of not properly handling the asylum status of migrants, but Greek Prime Minister Kyriakos Mitsotakis has denied the allegations.
The two countries are among those in Europe that have taken the most migrants in recent years, as the number of people travelling to escape conflict zones in Africa, Asia and the Middle East grows.
On Thursday, the director of the European council on refugees and exiles said the migrant crisis in Greece is the direct result of EU policies on blocking the onward movement of asylum seekers to more prosperous parts of Europe.
“The situation in Greece is the direct result of European policy and particularly the Greek-Turkey deal," Catherine Woollard said.
"So now the situation will also be exacerbated by the new law introduced by Greece."
At the start of November, Greece passed a law tightening its asylum procedures, drawing condemnation from human rights groups and migrant advocates.
The Pew Research Centre in the US said that between 3.9 million and 4.8 million unauthorised immigrants lived in Europe in 2017, most of whom were recently arrived young men.
These numbers were slightly lower than the previous year.
The study defined "unauthorised migrants" as foreigners who had entered the country illegally, those whose residence permits had expired, those under expulsion orders or asylum seekers with decisions pending on their status, Pew said.
Pew said that the figures accounted for less than one per cent of the continent’s population of more than 500 million.
The US researchers analysed data from across Europe.
Pew said the number of unauthorised migrants peaked in 2016 at between 4.1 and 5.3 million, adding it was likely that more than one million were living in Germany and the UK.