ZAGREB, Croatia (AP) — Thousands of Croatia's far-right supporters are marching in downtown Zagreb to protest an international convention they say indirectly legalizes gay marriages and gives rights to transgender people.

The protesters are singing patriotic songs and chanting slogans against Croatia's center-right government for approving the so-called Istanbul convention that was adopted by the European Council in 2011 but still hasn't been ratified by Croatia's parliament.

Croatia's conservative opposition and the Catholic Church — the organizers of Saturday's protest — say they are for combating violence against women and domestic violence, which is the main point of the convention, but are against its alleged introduction of "a third gender" into society.

Since joining the European Union in 2013, Croatia has been drifting toward the conservative far-right.