By Francesco Guarascio
BRUSSELS (Reuters) - The number of migrants seeking protection in the European Union soared by 68 percent in the first five months of 2015 compared with the year-earlier period, the EU said on Wednesday at a time of haggling between member states over how to share the burden.
EU ministers responsible for migrant issues will meet on Thursday to weigh details of a plan aimed at deterring migrants from making dangerous sea crossings to Europe while helping Mediterranean EU countries -- especially Italy and Greece -- bearing the brunt of the influx and struggling to cope.
Member states have rejected a mandatory scheme to share migrants proposed by the European Commission, the EU executive, and are negotiating on voluntary commitments. "The work is still ongoing," a diplomat told Reuters on Wednesday.
The European Asylum Support Office (EASO) gave no figure for the number of arriving migrants in the January-May 2015 period.
But the U.N. High Commissioner for Refugees said earlier that more than 135,000 migrants had arrived in Europe by sea in the first half of 2015, mostly landing in Greece and Italy.
EASO said that the full-year 2014 figure was already a record with more than 660,000 migrants seeking asylum in the EU's 28 countries plus Switzerland and Norway.
Many asylum seekers pitch up on the southern shores of Europe after risking their lives in overloaded boats dispatched by human traffickers dispatched across the Mediterranean.
Migrants come mainly from African and Middle Eastern countries plagued by conflict, human rights abuses and poverty.
In June, EU leaders endorsed ways to counter the migration crisis in the Mediterranean by sharing 60,000 refugees and asylum seekers over the next two years, but failed to decide precise national commitments to take people in.
According to the plan to be considered at the meeting in Luxembourg on Thursday, 20,000 refugees would be resettled in Europe directly from their countries of origin or transit, such as Syrians escaping war or displaced in Lebanon or Jordan.
Another 40,000 asylum seekers now in Italy and Greece would be transferred to other EU countries.
Some EU countries have made informal pledges to host migrants but an agreement on how to share out 60,000 migrants remains elusive. Ministers are aiming for a deal by the end of July to allow the plan to run from September.
In preparatory meetings, diplomats agreed to include Iraqis among the nationalities that would benefit from the relocation plan, diplomats said. The criteria initially set concerned only Syrians and Eritreans.
(Additional reporting by Robin Emmott; Editing by Mark Heinrich)