The European Union needs to find ways of speeding up the membership process for six Western Balkan candidate countries, European Council President Antonio Costa said on Thursday. "For us, the enlargement, namely to the Western Balkans, is the most important geopolitical investment that the European Union is doing," Costa said during a joint press briefing with Serbian President Aleksandar Vucic in Belgrade. Albania , Bosnia-Herzegovina , Kosovo , North Macedonia , Serbia and Montenegro have