A controversial plan to tackle Europe's refugee crisis has made no immediate impact on numbers of migrants reaching Greece from Turkey, as the Mediterranean neighbours sought to co-ordinate implementation of the multi-billion-euro deal.
More than 1,650 people have landed on Greek islands since the plan came into force overnight Saturday-to-Sunday, prompting Athens to urge EU states to send promised manpower and to call on Turkey to stop more smugglers' boats.
More than 50,000 migrants are now stuck in Greece after Balkan states to the north closed their borders, increasing the onus on Turkey to slow the flow of new arrivals to allow Greece to clear the backlog and put the new plan into effect.
"We have to make an uphill effort because implementation of this agreement will not be an easy issue," Greek prime minister Alexis Tsipras said on Monday, as he met EU migration commissioner Dimitris Avramopoulos.
“If a reduction of [refugee] flows does not occur, we will not be able to evacuate the islands successfully so that the deal can start to be implemented fully,” he added.
Mr Tsipras insisted that Greece, fellow EU states and Turkey “must move very swiftly and in a co-ordinated manner over the next few days to get the best possible result…Assistance in human resources must come quickly.”
When the deal was sealed last Friday, EU states agreed to dispatch 2,300 police officers and other staff to Greece, including translators and immigration experts, to implement it; so far, none have arrived, but France, Germany, the Netherlands and Romania have pledged to send personnel.
"We are at a crucial turning point," Mr Avramopoulos said after talks in Athens. "The management of the refugee crisis for Europe as a whole hinges on the progress and success of this agreement."
The plan makes provision for every Syrian landing on a Greek island from March 20th to be sent back to Turkey, in exchange for a compatriot now in a Turkish refugee camp, with the aim of deterring people from making illegal sea crossings.
New arrivals are being taken to registration centres that Greece has belatedly established on five Aegean islands; those seeking asylum will stay there while Greek and EU officials consider their applications.
On the Greek mainland, soldiers are helping expand accommodation facilities at several locations, as attempts continue to persuade migrants to leave the squalid Idomeni camp on the closed Greece-Macedonia border.
Germany has said that migrants are likely to be returned to Turkey only from April 4th, given the time needed to staff, plan and launch the process.
Personnel from Turkey are now on the Greek islands of Lesbos and Chios to help co-ordinate how the countries will implement a scheme that major rights groups call immoral and potentially illegal.
As part of the deal, the EU agreed accelerate talks on Turkey's accession bid; to double refugee aid for Ankara to six billion euros; and to let Turks travel without visas to the EU's passport-free Schengen zone by June.