The first boats carrying migrants being deported from Greece arrived in Turkey on Monday as part of a controversial EU plan aimed at easing mass migration to Europe.
The Greek state news agency ANA reported that some 250 migrants from Bangladesh, Pakistan, Sri Lanka and African nations would be sent back daily between Monday and Wednesday.
Germany expects to take in a first group of about 35 Syrians from Turkey on Monday, the German interior ministry said.
Several dozen others are expected to arrive in France, Finland and Portugal, according to German government source.
Non-Syrians will be deported while Syrians will be sent to refugee camps where they will replace those who will be directly resettled in Europe as part of the "one for one" plan agreed by EU leaders and Turkey earlier this year.
The first returns on Monday were carried out calmly, Ewa Moncure, spokeswoman for the EU border agency Frontex, who said that some 350 Frontex officers had arrived over the weekend for the operation.
Frontex reportedly has less than one-tenth of the staff needed to do the job and only a fraction of the necessary staff have so far arrived on the Greek islands to accompany the process.
Under the EU-Turkey agreement, any illegal migrant arriving to the five Greek islands after March 20 will be returned to Turkey, except those who are granted asylum in Greece. For every Syrian returned to Turkey, a Syrian refugee in Turkey will be relocated to the EU, up to 72,000 in all.
Officially, there are 2.7 million Syrian refugees in Turkey but authorities estimate that another 300,000 Syrians are in the country without ever having registered.
The number of refugees crossing illegally from Turkey to Greece is down to 400 a day from its peak of 6800 last October.
ECR home affairs spokesman Timothy Kirkhope, a UK Tory MEP, has argued that the EU should not be looking for quick fixes or 'silver bullet' policies during the migrant crisis at huge cost to the EU's budget.
Instead, he says the EU and member states need to work on "getting the basics right", including enhancing border control, increasing fingerprinting and the speed of processing asylum applications, as well as providing dignified living conditions for asylum seekers.
Further comment came from EPP leader Manfred Weber who said, "A key element in the solution of the migrant crisis is for Turkey to take back all people coming to Greece.
"But there are two sides to every coin. On the one hand we reduce the numbers of illegal migrants and on the other, we indicate legal channels to come to Europe to people who need our help, people from places like Aleppo.
"But there will be no 'refugee rebate' for Turkey when it comes to visa liberalisation for instance. The country has to implement all the visa rules and only then will the European Parliament discuss possible visa liberalisation.
"Now the time has come for all of us to start delivering, including those countries that have so far contributed little to manage the crisis. We have the will to succeed and this is a very important signal," said Weber.
The deal to deport asylum seekers from Greece to Turkey has come under criticism from rights groups.
Amnesty International accused Turkey of illegally forcing Syrians to return to their war-torn homeland - proof that Turkey is not a safe country for refugees, it says.
Save the Children, meanwhile, called the deal "illegal and inhumane", saying people told them they would kill themselves if sent back to Turkey.