The leaders of the European Union and the Western Balkans countries agreed to forge closer ties at a summit on Wednesday evening in Brussels.

Russia's war against Ukraine and the increasing geopolitical challenges underscore the need for ever closer relations, according to a joint statement issued by the EU's 27 members and five countries of the region.

The future of the Western Balkans lies within the European Union, the declaration stressed.

The leaders of Albania, Bosnia-Herzegovina, Montenegro, North Macedonia and Kosovo travelled to Brussels for the talks.

Serbian President Aleksandar Vučić decided not to attend the summit. The exact reasons for his decision were not immediately clear.

The European Union intends to encourage all six countries to undertake further reform efforts, which should eventually lead to EU membership.

"Enlargement is a geostrategic investment in peace, security, stability and prosperity," the declaration read.

"The urgencies of our time call for a sustained momentum. Aspiring members need to step up their reform efforts. In parallel, the Union needs to step up its internal groundwork and reforms."

EU candidate countries were urged to intensify their reform efforts at the summit, while the EU is to move ahead on internal reforms.

"The road ahead will not be easy. Some reforms will be difficult, but they are worth it. And I believe that our partners are committed to delivering," said European Council President António Costa.

Front-runner to join the bloc is Montenegro, which, according to a recent analysis by the European Commission, is the furthest along the membership process and is expected to conclude accession negotiations by the end of 2026 if it maintains its current pace of reforms.

Albania could be ready to conclude negotiations by the end of 2027, the commission said.

Since 2018, there have been regular meetings between the leaders of the EU and the Western Balkan countries. The next meeting is scheduled to take place in Montenegro in June.