Belgium's Prime Minister Alexander De Croo said on Thursday he was confident the leaders of the 27 European Union member states would find an agreement on financial aid to Ukraine.

He added there was no alternative to a compromise on Ukraine aid among the 27 EU member states and that such an agreement was crucial.

The summit on Thursday, called to resolve the issue, is seen as the last opportunity to reach agreement on a four-year plan for 50 billion euros ($54.2 billion) of economic aid for Ukraine - a plan that has hit fierce resistance from Hungary.

Outgoing Dutch Prime Minister Mark Rutte also said he was "cautiously optimistic" about reaching a deal, "if Hungary is willing to compromise." (Reporting by Bart Meijer and Piotr Lipinski)