BRUSSELS (AP) — A number of European Union countries are blocking a decision to resume a naval operation in the Mediterranean Sea over concerns that it might encourage migrants to set out from the Libyan coast in search of better lives in Europe, the EU’s top diplomat said Monday.

The naval mission, Operation Sophia, was launched in 2015 amid a wave of irregular migration from North Africa to Europe. The aim was to crack down on migrant smugglers and enforce a U.N. arms embargo on Libya.

But tension over how to distribute migrants picked up in the sea among EU member states, and claims that the naval presence might encourage smugglers, led Italy to block the deployment of further ships last year. It currently functions almost exclusively using aircraft and pilot-less drones.

“There are people who believe that more assessment has to be done to be sure that it’s not going to produce a pull effect,” EU foreign policy chief Josep Borrell told reporters in Brussels as he arrived to chair a meeting of the bloc’s foreign ministers.

“My analysis of the figures, the data, I am not convinced of that. But some believe it,” Borrell said. He cast doubt over whether the issue would be resolved this month, despite increasing international calls for help in ensuring that the arms embargo on Libya is respected.

Libya has been in turmoil since 2011, when a civil war toppled long-time dictator Moammar Gadhafi, who was later killed.

Borrell said “the situation on the ground is very, very bad.”