Marko Drobnjakovic, Associated Press
Migrants from Syria take a break at a park in Presevo, close to the Serbian border with Macedonia, 300 kilometers southeast of Belgrade, Serbia, Monday, June 22, 2015.

BRUSSELS — European Union ministers failed Thursday to agree on relocating 40,000 of the refugees making risky boat trips from North Africa to Italy and Greece and will try again later this month to broker a deal on how many people each country will accept.

"The debate we've had today has been difficult. It's a very sensitive issue," said Luxembourg Foreign Minister Jean Asselborn, whose country hosted Thursday's ministerial meeting. He said ministers will meet again July 20 to try to reach an agreement.

The stalemate came a day after the UN refugee agency announced that data from Greece, Italy, Malta and Spain showed 137,000 people arriving in those countries between January and June, 83 percent more than the same time last year. The United Nations High Commissioner for Refugees said 1,867 people died making the crossing, up from 588 a year earlier.

Asselborn said ministers did manage to agree how to distribute 20,000 refugees currently being housed outside Europe, but getting countries to commit to divide up the 40,000 making their way to Greece and Italy over the next two years was a step too far.

"We're not very far from the target but some countries need time to negotiate, time to adjust and that is why today we preferred to defer it to July 20," he said.

The inability to reach an agreement again exposes deep divisions within the EU over how to deal with the huge influx of migrants fleeing conflicts in Syria, Iraq and Africa.

When the EU decided in June to share among members the 40,000 refugees, European Commission President Jean-Claude Juncker called it "a very modest effort."