Brussels: Bosnia formally applied for membership of the European Union on Monday, although Brussels says it must carry out a series of reforms before the application can even be considered.
A war in Bosnia in 1990s, part of the breakup of Yugoslavia, killed some 100,000 people.
The country remains split along ethnic lines and economically impoverished, lagging behind its Balkan neighbours on the path towards the EU.
Sarajevo has wanted to apply on several occasions, but the 28-nation EU said each time it had to further improve its economy, justice system, rule of law, public administration and political institutions to be able to become a candidate - a message Brussels reiterated on Monday again.
"We see that our neighbour Croatia is already a member state, Montenegro is on its EU integration path, as well as Serbia.
Bosnia and Herzegovina is also a part of this continent," Dragan Covic, the chairman of Bosnia's presidency, said in submitting the application letter in Brussels."We are aware that this is our task, that we need to do it."
Bosnia must also adjust a 2008 pre-membership agreement to reflect changes after Croatia, also an ex-Yugoslav republic, joined the bloc in 2013.
The Dayton Agreement that ended the Bosnian war split the country into the largely Bosniak and Croat region of the Federation of Bosnia and Herzegovina and the mostly Serb region of Republika Srpska.
It also established a national government, whose presidency is shared by a Bosniak, a Croat and a Serb.
"It's the beginning" of a long journey, Enlargement Commissioner Johannes Hahn said."Membership is not possible in couple of months, or even a few years."
The Dutch foreign minister, Bert Koenders, added that Bosnia's application would only be considered after "meaningful progress in the implementation of the reform agenda is achieved", meaning Sarajevo would not be given candidate status for now.
In its latest report on Bosnia in 2015, the EU said it had actually fallen back on some issues, including "the conditions for the exercise of the freedom of expression" and the required judiciary reforms.
But Federica Mogherini, the head of foreign affairs for the EU, emphasised the positive message of the move on Monday for both Bosnia - with its complex matrix of governments in different regions and elaborate decision-making procedures - and the bloc, engulfed with multiple crises.
"I think it's good news first and foremost for the people of your country, who can see today that... if all the levels of government of the country move together towards a common goal, it can be achieved," she said.
"At a time when the Union is questioned from within," Mogherini said, the eagerness of European countries to join the EU "reminds us all of how lucky we are being able to live on a continent that has the ability of giving peace."