The Council of Europe has said it is alarmed that Poland’s rightwing government is moving to withdraw from a landmark international treaty aimed at preventing violence against women. Poland’s justice minister, Zbigniew Ziobro, said on Saturday that he would begin preparing the formal process to withdraw from the Istanbul convention on Monday. The treaty is the world’s first binding instrument to prevent and tackle violence against women, from marital rape to female genital mutilation. A previous centrist Polish government signed the treaty in 2012 and it was ratified in 2015, when Ziobro called it “an invention, a feminist creation aimed at justifying gay ideology”. The treaty was spearheaded by the Council of Europe, the continent’s oldest human rights organisation, and its secretary general, Marija Pejčinović Burić, condemned the rightwing Law and Justice party (PiS) government’s plan to withdraw. “Leaving the Istanbul convention would be highly regrettable and a major step backwards in the protection of women against violence in Europe,” she said in a statement on Sunday. “If there are any misconceptions or misunderstandings about the convention, we are ready to clarify them in a constructive dialogue.” PiS and its coalition partners closely align themselves with the Catholic church and promote a conservative social agenda. Hostility to gay rights was one of the main issues promoted by the president, Andrzej Duda, during a successful re-election campaign this month. About 2,000 people marched in Warsaw on Friday to protest against the government’s withdrawal plan. There was also outrage from several members of the European parliament, with Iratxe García Pérez, the Spanish leader of the Socialist group, calling the decision “disgraceful”. “I stand with Polish citizens taking [to] the streets to demand respect for women’s rights,” she tweeted. The leader of the EU parliament’s Renew Europe group, the former Romanian prime minister Dacian Cioloş, tweeted: “Using the fight against the Istanbul convention as an instrument to display its conservatism is a new pitiful and pathetic move by some within the PiS government.” The Belgian MEP Guy Verhofstadt said the decision was “scandalous”, adding that “violence is not a traditional value”. The Council of Europe emphasised that the Istanbul convention’s sole objective is to combat violence against women and domestic violence. The treaty does not explicitly mention same-sex marriage. That has not stopped the backlash to it in Hungary and in Slovakia, where the parliament rejected the treaty, insisting, without proof, that it is at odds with the country’s constitutional definition of marriage as a heterosexual union. The Strasbourg-based Council of Europe, which is separate from the EU, has no binding powers but brings together 47 member states to make recommendations on rights and democracy.