Another ferry from the island of Chios is also expected to leave later.

A total of roughly 750 people will returned from the Greek islands by Wednesday, according to Greece’s state news agency.

Turkey has made preparations to receive around 500 people in Dikili, western Turkey.

"We have been in touch with the Greek authorities and said we could take 500 people and they have given us 400 names. Tomorrow it's possible that this figure could change," Turkish interior minister Efkan Ala was quoted as saying by AFP on Sunday.

Ala suggested citizens of countries like Afghanistan, Iraq and Pakistan would be returned to their home countries.

He said Syrians would be sent to refugee camps to replace those who will be directly resettled in Europe as part of the “one for one” plan.

Under the EU-Turkey deal, aimed at discouraging people from using irregular migration routes into Europe, Greece would send back everyone who fails to apply for asylum, or if their claim is rejected.

For each returned Syrian, the EU agreed to take in another Syrian directly from Turkey.

The deal has been heavily criticised by rights group who say mass return of refugees is contrary to international law and warn that Turkey is not a safe country for many of them.

“This is the first day of a very difficult time for refugee rights. Despite the serious legal gaps and lack of adequate protection in Turkey, the EU is forging ahead with a dangerous deal,” Giorgos Kosmopoulos, head of Amnesty International in Greece, told the Associated Press.

Migrants in Chios have protested against their planned return to Turkey, saying they were unaware of that possibility, and complained about the lack of information on asylum procedure.

Around 4,000 migrants and refugees have been detained on Greek islands since the EU-Turkey agreement came into force on 20 March.

Daily arrivals have dropped to about 300-400 from the previous 2,000.

According to the UN’s refugee agency, 51,000 people have been stranded in Greece after northern countries closed their borders.

Germany: More deals needed

Germany's interior minister Thomas de Maiziere suggested on Sunday that deals with northern African countries may be needed to prevent more migrant arrivals.

Germany, which took in more than one million refugees and migrants last year, has already seen arrivals drop sharply to 140 a day on its Austrian border, he told Tagesspiegel am Sonntag newspaper.

“I can say with a great deal of caution that the peak of the refugee crisis is behind us,” he said.

Be he added that if people start coming through alternative routes, like Libya and Italy, similar deals might be necessary as with Turkey.

“If, once more, more people come via this route, we will need to search for similar solutions as we did with Turkey and also enter into negotiations with North African countries,” he said.

Austria has meanwhile seen around a 1,500 pro-migrant protesters clash with police at the Brenner border crossing with Italy.

It comes after Austrian defence minister Peter Doskozil said on Saturday that soldiers would be deployed at the key transit point, as fears grow that migrants might start using the Mediterranean route to Italy.

“As the EU's external borders are not yet effectively protected, Austria will soon ramp up strict border controls. That means massive border controls at the Brenner Pass, and with soldiers,” Doskozil said.