European Union leaders are set to welcome Croatia as the 28th member of the bloc, offering new hope for other Balkan nations working to join the EU.

Officials said in Brussels Friday they had approved Zagreb's membership, concluding six years of tough negotiations.

EU Commission President Jose Manuel Barroso said he hoped everything would be in place Croatia to become the newest member of the EU by July 1, 2013.

The news came as Croatia prepared to celebrate 20 years of independence after the collapse of the former Yugoslavia.

U.S. Secretary of State Hillary Clinton said Croatia had overcome many challenges in that time, and now has a “secure future” as a part of NATO and upcoming member of the European Union.

Croatia's accession treaty should be concluded by the end of this year. It then has to be ratified by the parliaments of all 27 EU states.

European Council President Herman van Rompuy said Friday that Zagreb's success would bring “new momentum” to the accession bids of Albania, Bosnia, Macedonia, Serbia and Montenegro.

Croatia started EU membership talks in 2005. It will be the second former Yugoslav nation to join the EU, following Slovenia.