"That decision carries great importance for Croatia and all its citizens, but it also fills with joy the rest of us in the region because it is another step in the realisation of a common vision of a united, democratic and prosperous Europe," read the message.
Serbia and Montenegro is scheduled to start negotiations on a Stabilisation and Association Agreement with the EU on Monday.
"The progress in drawing closer to the European Union achieved by both Croatia and Serbia and Montenegro will certainly give new impetus to the further development of our bilateral relations as well as to the overall Europeanisation of the region we belong to," read the note.
Marovic wished Mesic and all Croatian citizens success in the continuation of the process of EU integration, adding they would continue to have the full support of Serbia and Montenegro.