Thousands of Croats have rallied in the capital, Zagreb, against an international agreement designed to protect women, saying it threatened traditional values.
The Croatian government last week approved the Istanbul Convention that was adopted by the Council of Europe in 2011, but still has not been ratified by the Croatian parliament.
Demonstrators said the convention would legitimize same-sex marriage and improve rights for transgender people.
Women's rights groups staged a counterprotest the same day. They pointed out that polls suggest two-thirds of Croats support the convention.
The protest against the convention was organized by Croatia's conservative opposition and the Catholic Church. Both oppose the ratification, insisting that it introduces a “third gender.”
Nearly 90 percent of Croatia's 4.2 million people are Roman Catholics and the church plays an important role in society.
The convention has so far been ratified by 28 countries, including 17 European Union member states.
Croatia became the bloc's newest member in 2013.