European diplomats are claiming a breakthrough in the continent’s migration crisis after reporting that Turkey has agreed to take back people not qualifying for asylum in the EU.

The agreement came as the EU statistics agency reported that the number of people applying for asylum in the EU more than doubled in 2015, reaching a record 1.26 million. EU leaders are preparing for an emergency summit on Monday aimed at getting to grips with the biggest movement of refugees and migrants since the end of the second world war.

Senior EU diplomats said that in negotiations on Thursday with Frans Timmermans, the vice-president of the European commission, the Turkish prime minister, Ahmet Davutoğlu, pledged that all “economic migrants” arriving in Greece and not qualifying for asylum could be returned to Turkey.

The “agreement in principle” was hailed in Brussels as a breakthrough. Greece has been trying for more than two months to return almost 900 people to Turkey only to face stalemate, though more than 300 were readmitted to Turkey this week.

“Ankara said this will continue,” a senior diplomat said.

However, the chances of this development becoming part of the answer to Europe’s crisis are slim. In order to have the scheme fully functioning, Turkey would need to strike readmission and visa deals with about 70 other countries so that it could return people to, say, Morocco, Pakistan or Afghanistan. This will not happen quickly.

“Readmission will not be immediately operational,” said the diplomat. “Davutoğlu has agreed to do that over time. Turkey needs readmission agreements with other countries first, otherwise it won’t take them back [from Greece].”

Senior sources in Brussels further reported that as of Friday the identification and registration of migrants arriving on Greek islands from Turkey was complete. All were being registered, as opposed to a mere 8% several months ago.

In Athens, officials reiterated that Greece is struggling to accommodate refugees and migrants. The country is hosting 32,000 such people – a third trapped in increasingly squalid conditions in a makeshift camp outside Idomeni on the Greek-Macedonian border.

With about 1,000 new arrivals every day – more than half women and children – NGOs said the threat of an outbreak of disease had become ever more real.

“This was supposed to be a transition camp designed for 1,500 people, not 12,000,” said Ida Torstensson, the head of water and sanitation for Médecins Sans Frontières in Idomeni. Children with compromised immune systems had been treated for diarrhoea and vomiting.

The buildup came despite Greek authorities’ attempts to control flows by quarantining new arrivals on Lesbos and other Aegean islands in an attempt to reduce pressure on the capital, where reception centres are under massive strain.

Passenger terminals at Athens’s main port, Piraeus, and former international airport are overflowing. Victoria Square, the major meeting point for migrants and refugees, has seen hundreds sleeping outdoors in foetid, dank conditions.

The Greek migration minister, Yannis Mouzalas, said the beleaguered government would have 15,000 places to accommodate newcomers by next week “with 15,000 more the week after that”. Abandoned military camps, hotels, sports stadiums, children’s summer camps, parks and public buildings have all been requisitioned to house refugees.

A concerted effort to reduce the numbers coming across the Aegean to Greece will be the focus of Monday’s EU-Turkey summit in Brussels. The European council president, Donald Tusk, who on Thursday urged economic migrants to stay away from Europe, struck an optimistic note on Friday, saying a consensus was emerging on tackling the migration crisis.

Brussels stepped up warnings to member states to take urgent action to resolve the crisis by agreeing on plans to redistribute asylum seekers around Europe.

The EU’s migration commissioner, Dimitris Avramopoulos, echoed apocalyptic warnings from other European leaders when he argued the EU had to save its passport-free Schengen travel zone in order to preserve decades of European integration.



“All that we have achieved in the last 60 years is at stake and we have to do what we can to uphold and safeguard these achievements,” he said.



The action plan he published, revealed in the Guardian on Wednesday, calls on member states to lift border controls as quickly as possible and with “a clear target date of November 2016”.

Since September, eight countries have reintroduced border checks, aimed at preventing large numbers of refugees and migrants entering. Avramopoulos said the actions were in line with EU rules, which allow open borders to be suspended in an emergency. But he urged countries to work towards reopening them as soon as possible, while increasing controls on Europe’s external frontiers.

“We cannot have free movement if we cannot manage our external border effectively,” he said.

A clampdown on migrants would have a big impact on Afghans, as many European countries say people fleeing the war-torn country are no longer eligible for asylum, unlike Syrians and Iraqis. As the data from the EU statistics agency, Eurostat, shows, Afghans were the second-largest group of people claiming asylum in 2015, with 178,200 people seeking protection. Iraqis were the next largest group, with 121,500 asylum claims, more than seven times the total for 2014.



Smaller numbers of Kosovans, Albanians, Pakistanis, Eritreans and Nigerians also sought asylum in Europe.



More than a third of all applicants in 2015 went to Germany, followed by Hungary and Sweden. Relative to population size, Hungary took the highest number of first-time applicants, 17,699 per million inhabitants, compared with Sweden, which took 16,016. Hungary’s prime minister, Viktor Orbán, has since fenced off his country’s 110-mile border with Croatia and vowed he will not take a quota of refugees assigned to the country under an EU relocation scheme.



Avramopoulos maintains that all countries must respect the EU law the quotas are based on. “They must understand that they have to comply with the decisions that we have taken all together,” he said.