Some 20,000 Muslims from Croatia and abroad gathered in the Adriatic port city of Rijeka on Saturday to inaugurate an Islamic centre and the third mosque in the staunchly Catholic country.
"Multiculturalism and diversity are among basic values on which the European Union is built," the head of EU delegation here, Paul Vandoren, said in a reminder that Croatia was set to join the bloc on July 1.
Croatian President Ivo Josipovic said the centre showed "that diversities are possible and good".
"Croatia is a country of the rule of law and religious freedom," he said at the ceremony.
Almost 87 percent of Croatia's 4.2 million inhabitants are Roman Catholics, while Muslims make up only some 1.5 percent of the population.
Of Croatia's 63,000 Muslims, around 10,000 live in the Rijeka region.
"The building of this mosque was crucial for me because my daughter will go to kindergarten here," Sadmir Kukuruzovic, a 27-year-old truck driver from Rijeka, told AFP.
The Islamic centre, on a hill overlooking Kvarner bay, consists of a large silver mosque with a 23-metre (75-foot) minaret, as well as a kindergarten, school, library and clinic.
The project was estimated to have cost about 10 million euros ($13 million), largely financed by Qatar's emir, Sheikh Hamad bin Khalifa al-Thani.
Aziz Emini, an ethnic Albanian from Macedonia now living in Germany, said his family "came to witness real peace among religions".
"Croatia, which tomorrow will enter the Europan Union, could serve as an example of integration of Muslims in Europe," the 47-year-old baker said.
Mufti Aziz Hasanovic, Croatia's Islamic leader, said the centre was a "message to both Europe and the world how to build good relations in a multicultural society".
Construction of the centre, designed by a prominent Croatian, the late Dusan Dzamonja, began in October 2009 although the initial idea was launched back in 1968.
Qatari Minister of Endowments and Islamic Affairs Ghaith bin Mubarak Al-Kuwari and a number of Croatia's top officials and Catholic Church representatives attended the ceremony, as well as top Muslim clerics from the region and several European countries.
"For Muslims, Croatia is good place to live in and could serve as an example to other European countries," said the Muslim member of neighbouring Bosnia's tripartite presidency, Bakir Izetbegovic.
"Today's event sends good signals to the whole world and notably to the region" of the Balkans, ravaged by inter-ethnic wars in the 1990s, he said.
The Rijeka mosque is Croatia's third. The biggest is in the capital Zagreb, while another is found in the eastern town of Gunja, on the border with Bosnia.