The EU wants to solve the asylum rules dispute before June, when the number of migrants making the dangerous journey across the Mediterranean rises with the onset of warmer weather

EU ministers on Thursday started their countdown toward overhauling their asylum rules by a June deadline but struggled to settle a row over refugee quotas that has dogged them since the migration crisis erupted in 2015.

The minister from Bulgaria, which holds the six-month rotating EU presidency ending June 30, said agreement was emerging over a German-backed proposal to tackle the easier problems first and save the refugee row until last.

"My brief answer is yes. We have almost agreed to this," Interior Minister Valentin Radev told a final press conference when asked about the proposal.

"Yes we agreed first to look at the text article by article," he added through an interpreter.

German Interior Minister Thomas de Maiziere warned it would be "difficult" to reach a June deal on quotas and suggested concentrating first on "easier" asylum reforms linked to family reunification and other issues.

"I heard very moderate voices today from my eastern European colleagues," de Maiziere said before adding there was "no substantial change in their positions."

But De Maiziere, whose country has admitted the largest number of asylum seekers in the bloc, said he cannot imagine reform without the principle requiring every member country to take in refugees.

Hungary, Poland, the Czech Republic and Slovakia have either refused outright or resisted taking in refugees since the European Commission, the EU executive, first pushed through temporary quotas in 2015 as a way to ease the burden on frontline states Italy and Greece.

The summer of that year saw a surge in mass drownings in the Mediterranean as Europe's worst migration crisis since World War II peaked with hundreds of thousands of people fleeing war and poverty in the Middle East and elsewhere.

Under an emergency plan, EU member countries agreed to relocate to other parts of the bloc 160,000 Syrians and other refugees from Italy and Greece within two years.

Only 33,000 people have been relocated as most people made their own way to Germany and other wealthy northern countries amid the chaotic EU response to the crisis.

Little, if any progress on quotas has been made since talks on asylum reform began in 2016.

EU leaders meeting in Brussels last month set a June deadline for an overhaul of the so-called Dublin rules to create a permanent mechanism for all member states to admit refugees in the event of a new emergency.

Besides being the end of the Bulgarian presidency, June is when migrant flows across the Mediterranean tend to increase with the warmer weather.

- 'Don't be pessimistic' -

Under existing rules, countries where migrants first arrive are required to process asylum requests, putting a heavy burden on Greece and Italy, the current main entry points to Europe.

EU cooperation deals with Turkey and Libya, the main transit countries, have helped to slow, at least for now, the flow of migrants to Europe since its 2015 peak.

But European Migration Commissioner Dimitris Avramopoulos warned that the crisis could flare anew along the EU's long external borders as he pushed for asylum reform.

He said EU countries would continue working under the Bulgarian presidency toward establishing fairer asylum rules enshrining the principle of solidarity.

"Don't be pessimistic," Avramopoulos told the closing press conference.

A diplomat who asked not to be named said the hot potato of refugee quotas would be settled toward the end by a political decision at "a higher level" than that of ministers.