European Union leaders were gathering Thursday to examine new ways to stop migrants entering Europe, desperate to ensure that their differences over managing the flows do not tear the 28-nation bloc apart.

The number of people arriving in Europe seeking sanctuary or better lives has dropped significantly, but anti-migrant parties have consolidated their powers, winning votes as they exploit fear of foreigners.

The political crisis caused by the EU’s inability to share responsibility for those entering is undermining German Chancellor Angela Merkel’s leadership. It’s also helped bring an anti-European government to power in Italy.

Italy, the main landing point for migrants along with Greece, has begun to refuse entry to ships carrying people rescued from the Mediterranean Sea. The EU’s smallest member state, the island of Malta, is also resisting appeals to do more. France has been involved, criticizing Rome in a major diplomatic row.

“Europe has many challenges, but that of migration could determine the fate of the European Union,” Merkel told German lawmakers Thursday before heading for a two-day summit in Brussels.

Merkel is fighting a battle at home and abroad against critics who accuse her of endangering European security with her welcoming approach to migrants. Her conservative coalition is under pressure from the far-right Alternative for Germany.

The party has received a surge in support since 2015 – when well over one million people entered Europe, mostly fleeing conflicts in Syria and Iraq – and populist leaders in southern and eastern Europe have rejected her calls for a wholesale reform of Europe’s migration system.

With Merkel’s coalition allies demanding that migrants be turned away at the border with Austria, EU officials fear any such move would set off a domino effect. Austria in turn could close its border with Italy, and Rome might then close its ports.

The leaders will discuss the establishment of Orwellian-sounding “regional disembarkation platforms,” in an effort to prevent people from reaching Europe. The plan, yet to be fleshed out, involves placing people leaving Africa bound for Europe in centers in countries like Algeria, Egypt, Libya, Morocco, Niger and Tunisia.

“A precondition for a genuine EU migration policy is that Europeans effectively decide who enters European territory,” EU Council President Donald Tusk said in an invitation letter to the leaders. “Failure to achieve this goal would in fact be a manifestation of our weakness.”

The scheme is likely to prove extremely expensive – and no African country has expressed an interest so far in taking part. Big questions also remain over whether people would be left languishing at these centers with little hope of getting to Europe and no means or will to return home. Under international law, people legitimately in fear for their lives and safety are within their rights to try to reach a safe place and apply for asylum.

On the island of Malta, meanwhile, screening began Thursday for 234 people who spent nearly a week at sea on a humanitarian rescue vessel, to determine whether they are eligible for asylum and relocation to one of eight EU nations.

The government said three babies and three adults were being treated in hospital.

Malta Prime Minister Joseph Muscat opened the country’s main port to the German-run ship Lifeline after other EU nations agreed to accept some of the people. He said those deemed “economic migrants” will be sent back to where they came from.

Maltese officials seized the ship, citing irregularities in the rescue. The captain is under investigation.