US Vice President Joe Biden arrived in Zagreb on Wednesday for a summit of Southeast European leaders dedicated to the region's integration with the EU and NATO.
Biden will participate in the meeting of the Brdo-Brijuni Process, a regional political initiative bringing together former Yugoslav countries and Albania.
Biden is the highest US official to visit Croatia since Barack Obama took up office as US President.
Apart from presidents of the countries in the region, the Zagreb summit will also be attended by European Council President Donald Tusk and Austrian President Heinz Fischer.
Croatia, as the host of the event, expects the summit to help its neighbours get closer to the West and Biden's visit is seen as a big return of the United States on the regional scene after its crucial role in stopping the war in Bosnia and Herzegovina in 1995.
The summit is taking place amidst a refugee crisis on the Balkan route, with Europe being on a heightened security alert after terrorist attacks in Paris on November 13 and several terrorist attacks in Bosnia and Herzegovina.
Slovenia and Croatia, which launched the Brdo-Brijuni Process, do not want the refugee crisis to overshadow other problems in their neighbourhood such as internal conflicts in Montenegro over the country's expected accession to NATO, unresolved relations between Serbia and Kosovo and the Islamisation of the traditionally secular Albanian population in Kosovo, Macedonia and Albania.