European Union leaders gathering in Brussels are expected to endorse the formal start of accession talks for Montenegro with the bloc.
A vote on Montenegro's bid by the 27-member union is on the agenda of the Belgian meeting.
On June 26, EU foreign ministers agreed that Montenegro had carried out reforms and was ready to start talks on becoming a member of the bloc.
Swedish Foreign Minister Carl Bildt warned, however, that concerns about organized crime and corruption in the Balkans -- and especially, the illegal drugs trade -- could complicate Montenegro's negotiations.
Montenegro hopes the EU accession process will help it overcome a serious economic crisis.
It is expected to take years for Montenegro to become a member of the EU once the accession process formally begins.
Among other former Yugoslav states, Slovenia is already an EU member while Croatia is slated to join in mid-2013.
Based on reporting by Reuters, AFP, and dpa