ZAGREB, 3 Sept (Hina) - Enlargement is the most important geopolitical investment in the security of the European Union, European Council President Antonio Costa said in Zagreb.

“Enlargement to Ukraine, enlargement to Moldova and to the Western Balkan countries. It is a very demanding process, but we need to focus and prioritise on this and continue to work with all these countries to ensure that in this institutional cycle we achieve with success this process," Costa told a joint press conference with Croatian Prime Minister Andrej Plenković.

Plenković said that Croatia supports further enlargement based on each candidate country’s fulfilment of individual criteria.

"We want this process to be fair, dynamic and beneficial to the countries wishing to join the EU after Croatia, but also to ensure that the Union's overall functionality, in terms of its budget and decision-making processes, remains at the highest level," he said.

Costa arrived in Zagreb as part of his tour of EU member states on the Union's main priorities ahead of negotiations on the new multiannual budget next year.

In July, the European Commission proposed what it called its "most ambitious" seven-year budget so far, worth €2 trillion for the 2028–2034 period.

"Every voice matters, and it is very important to listen to the different leaders to design our main priorities and our agenda for the coming months," Costa said.

The European Council president began his tour in Slovenia on Monday. He will visit Austria on Wednesday, Bulgaria and Romania on Thursday, and will conclude the week with trips to the Czech Republic and the Netherlands.

Key topics in his discussions with the European leaders include defence, Ukraine, EU enlargement, the Middle East, the Multiannual Financial Framework, trade and competitiveness.