"We have received a confirmation that Croatia is becoming the 28th member of the Union. This is a historic moment, a time for celebration. ... This government deserves the greatest credit for the fact that Croatia is becoming the 28th member of the Union and the Croatian language the 24th official language of the EU," Kosor told reporters in the Croatian Journalists Association's building where she was watching a plenary session of the European Parliament in Brussels in the company of government ministers and officials of her HDZ party.

"The dream we have been dreaming for a long time has become a reality," Kosor said, quoting the first Croatian President Franjo Tudjman as saying that "Croatia must be a part of the European family of states and nations." She said she was dedicating this special moment to him and to veterans of the 1991-1995 Croatian Homeland War.

Looking back on the negotiating process, Kosor said that Croatia had had the most difficult negotiations so far.

"We had to implement comprehensive reforms and meet as many as 400 benchmarks," she said, noting that the chapters, or policy areas dealing with competition, judiciary and agriculture had turned out to be the toughest. She recalled that Croatia had been negotiating its EU membership "while still carrying the burden of an imposed war" and against a backdrop of the economic crisis in the EU.

Kosor said she was pleased that Croatia was joining the EU on its own. "We are the first country, since Greece in 1982, to enter the EU on our own," she said.

The premier criticised the Croatian media for bias, especially the public broadcaster HRT for withholding news that she had been invited to Brussels to sign the Accession Treaty.

Kosor thanked the Croatian negotiators, the Ministry of Foreign Affairs and European Integration, government ministers, and all previous governments that had worked on the European project.

Croatia's Accession Treaty is due to be signed in Brussels on December 9.