The European Commission has presented far reaching proposals on changing Europe's migration and asylum policies in the light of the influx of more than one million refugees in the past year.
The commission wants to scrap the so-called Dublin Regulation which requires that refugees seek asylum in the first EU country they enter, which is usually Italy or Greece.
Instead, a new mechanism for migrants would be distributed to other member states according to a country's population size, unemployment level and relative wealth.
In simple terms the Dublin Regulation means that anyone seeking asylum in the EU should do it in the first country they enter.
However, that policy has been in disarray in the past couple of years.
Hundreds of thousands of migrants and refugees have entered Italy from north Africa and into Greece from Turkey.
In most cases they did not apply for asylum but moved on - often effectively being waved through - to countries like Germany and Sweden.
However, since the concept of open borders depends on the Dublin Regulation working effectively, a complete overhaul is believed to be necessary.
The commission is offering a number of options.
One is that the Dublin Regulation remains in place, and that countries feeling the pressure - namely Italy and Greece - could, under a minor tweaking of the rules - call for help.
But it is likely to push a more radical option.
Instead of Greece and Italy having to take the burden, a formula would be worked out based on population size, unemployment level, GDP and other criteria, so that migrants entering the EU would be distributed to different member states.
Such a plan though is likely to face intense opposition from member states, particularly in Eastern Europe.
Sharp fall in number of migrants arriving in Greece
A deal between the European Union and Turkey appears to be showing signs of slowing the flow of migrants and refugees to the Greek islands.
However, many people were still trying to cross the sea and the route remained far from sealed off.
Three days after the EU-Turkey deal came into force, new arrivals on the Greek islands from Turkey dropped to 68 in the 24 hours to this morning from 225 the previous day, data from the Greek migration ministry showed.
The numbers fluctuate daily and it was unclear if the decline was a direct result of the accord, under which migrants and refugees who use irregular sea crossings in the Aegean to get into Greece are being sent back to Turkey.
"We had a very low influx from the other side of the Aegean... which we consider positive," said Greek government spokesman George Kyritsis.
Since the deal was implemented on Monday, 202 people, the majority from Pakistan, have been returned from Greece. Greek and Turkish officials say more could be sent back this week.
But despite the returns, and tighter security along Turkey's coast, people were still trying to make the crossing.
Turkish authorities detained several groups at sea shortly after dawn, including about 40 Iraqis, some of whom set sail in a small dinghy from a cove 20km south of the town of Dikili.
Some were left on the beach as the dinghy was too small to carry them all. They watched as the Turkish coastguard intercepted the vessel moments later.
"Greece does not want to host us. Turkey is not allowing us. Where should we go? We drown in the sea with our children, that's it," said one Iraqi man.
They were later put on buses and taken to Dikili, where a small reception centre has been set up in the port to process migrants sent back from Greece.
Around 15 Pakistani migrants were also intercepted and brought to the town.
On a road outside Dikili, nine Syrian Palestinians, their belongings in rubbish bags slung over their backs, were trying to find transport after abandoning their efforts to cross, deciding the groups they planned to join were too big and the boats too small.
They had fled from the Palestinian refugee camp of Yarmouk on the outskirts of the Syrian capital Damascus. Some said they wanted to cross, others said they now hope to be settled in a refugee camp in Turkey.
"This agreement is not about Syrians or Palestinians. Where can we go if we go back to our land?" one said of the EU-Turkey deal.
Under the accord, the EU will take in thousands of Syrian refugees directly from Turkey and reward it with financial aid, visa-free travel and progress in its EU membership negotiations.
Human rights campaigners have challenged the legality of the deal, saying it rides roughshod over the rights of people displaced by war and question whether Turkey has sufficient safeguards in place to qualify as a safe country for refugees.
European officials say it is essential for Turkey to adopt tighter regulation on temporary protection for Syrians, according to people familiar with an internal European Commission report.
A Turkish official told Reuters the regulation had been agreed by the cabinet and sent to President Tayyip Erdogan's office late last night, where it was awaiting approval, but gave no further details.
Non-Syrians returned from Greece are being taken to a "reception and removal" centre in the Turkish town of Kirklareli near the Bulgarian border, from where they are expected to be deported to their home countries.
Returned Syrians are expected to be taken initially to a camp in the southern town of Osmaniye, from where those who have the means will be allowed to settle elsewhere in Turkey among an existing Syrian migrant population of 2.8 million, Turkish officials have said.
Greece has reported a spike in the number of asylum applications of individuals who have arrived since 20 March, the date the first phase of the EU accord took effect and new arrivals were detained in holding centres.