BRUSSELS — European Union leaders will look to boost aid to Greece as the Balkan migrant route is effectively sealed, using Monday’s summit as an attempt to restore unity among the 28 member nations after months of increasing bickering and go-it-alone policies, according to a draft statement Sunday.

The leaders will also try to persuade Turkey’s prime minister to slow the flow of migrants traveling to Europe and take back thousands who don’t qualify for asylum.

In a draft summit statement produced Sunday, the EU leaders will conclude that “irregular flows of migrants along the Western Balkans route are coming to an end; this route is now closed.” Because of this, the statement added that “the EU will stand by Greece in this difficult moment and will do its utmost to help manage the situation.”

“This is a collective EU responsibility requiring fast and efficient mobilization,” it said in a clear commitment to end the bickering. It said that aid to Greece should center on urgent humanitarian aid as well as managing its borders and making sure that migrants not in need of international protections are quickly returned to Turkey.

The statement will be assessed by the 28 leaders after they have met with Turkish Prime Minister Ahmet Davutoglu.

Late Sunday evening, German Chancellor Angela Merkel and Dutch Premier Mark Rutte met with Davutoglu to prepare for the summit.

At least 25 migrants drowned off the Turkish coast while trying to reach Greece on Sunday, Turkey’s state-run news agency reported. The coast guard launched a search-and-rescue mission for other migrants believed to be missing.

Ankara is central to easing Europe’s refugee pressures. More than 2,000 people arrive daily from Turkey to Greece, where many have been stranded as countries on the main migrant route through the Balkans aim to stop them from moving north.

The bloc has offered several sweeteners to get Turkish authorities to crack down on migrant movements. Some $3.3 billion will be made available for Syrian refugees. Turkey’s long-coveted EU membership process is being sped up, as are moves to ease EU visa requirements. Summit meetings like these are also part of the package.

Ahead of the summit, the European Commission trumpeted the availability of aid to help Syrian school children and provide food aid. It said that a new “road map” on visa liberalization for Turkey had also been submitted.