The trio are frustrated at the lack of progress in joining the EU.
ADVERTISEMENTSerbia, Albania and North Macedonia will attend a Brussels summit tomorrow on integration with the EU despite threatening earlier to boycott it amid frustration about progress on joining the bloc.
All three countries have been given the status of candidates for EU membership but neither has made significant progress in recent years.
North Macedonia's Prime Minister Dimitar Kovacevski said the three nations would "reaffirm the position that Northern Macedonia, Albania and Serbia have a European future".
He said the leaders would convey their views on EU integration together at the summit on Thursday.
But, he said in a Facebook post, unless there was progress on integration it would be "a blow to the EU credibility in the Balkans".
Albanian Prime Minister Edi Rama also confirmed that his country would attend the summit but said that "there wouldn't be much to hear about us".
North Macedonia received candidate status in 2005, Serbia in 2012 and Albania in 2014. Out of the three, only Serbia has started formal accession talks.
North Macedonia and Albania, whose respective bids are considered to be "coupled", have been waiting for more than two years to see the official start of negotiations.
The blockade stems from the veto of Bulgaria, which has a number of historical and cultural demands on North Macedonia. Bulgaria's new prime minister, Kiril Petkov, has signalled his intention to lift the impasse, but his plan has caused rifts within the ruling coalition.
Ahead of the summit, EU enlargement commissioner Oliver Varhelyi tweeted that former Prime Minister Boyko Borissov, who leads the opposition GERB party, had accepted that North Macedonia proceed with accession negotiations.
"We expect government [to make the] necessary proposals to Parliament today so Europe can move forward," Varhelyi tweeted.
Rama said that it was "too early to be optimistic" and implied that Albania would still criticise Bulgaria over its position on accession talks.
The summit is scheduled to take place on Thursday morning -- ahead of a general meeting of the European Council -- and is meant to address progress on EU integration and the war in Ukraine.
Possible snub over Bulgaria
Serbian President Aleksandar Vučić had said on Tuesday that he had discussed whether to attend the summit with the leaders of Albania and North Macedonia.
"It seems that another 'No, sorry!' is gonna be what we will hear at the end!" tweeted Rama. "The whole Union kidnapped by Bulgaria it is not a good spectacle to watch! What to do there?!"
Bosnia and Herzegovina, Montenegro and Kosovo were still expected to attend.
Beginning EU membership talks requires unanimity between the 27 EU member states.
The Balkan meeting is set to take place ahead of an EU council meeting where member states are likely to endorse giving EU candidate status to Ukraine and Moldova.