WARSAW, Poland (AP) — Throngs of protesters vented anger Friday across Poland over a top court ruling that declared abortions of fetuses with congenital defects unconstitutional, effectively narrowing one of Europe’s strictest abortion laws.

The hundreds of protesters who gathered in many cities wearing protective masks defied a COVID-19-related ban on gatherings that was imposed nationwide.

Police vans and units in riot gear were dispatched to guard the Warsaw house of the leader of Poland's right-wing ruling party, Jaroslaw Kaczynski. An angry crowd of mostly young people confronted the cordon with chants of “This is war” and vulgar calls for the ruling team to step down.

They also had posters reading “You Have Blood on Your Hands" and “You are Building Women's Hell.”

Officers used bullhorns to warn people the gathering was illegal. It was not clear if Kaczynski was home.

Protesters also marched through other big cities, including Krakow, Wroclaw, Szczecin and Katowice.

A protest also took place outside Kaczynski's home Thursday night, after the Constitutional Court presented its abortion law ruling. Police used tear gas and detained 15 people then.

Opposition parties in Poland, the European Union's human rights commissioner and international human rights organizations criticized the court's decision as violating women's rights. It leaves a pregnancy endangering a woman’s health or life, or resulting from rape or other illegal act as the only legal grounds for obtaining an abortion.

The decision takes effect when it is officially published in the Journal of Laws, which could happen within days or weeks.

Critics noted the ruling was issued at a time when street actions are prohibited. Previous attempts to restrict abortion since Kaczynski's Law and Justice party came to power in 2015 were scrapped following mass nationwide street protests.

The Constitutional Court's decision came in response to a motion from right-wing lawmakers who argued that terminating a pregnancy due to fetal defects — the most common reason cited for legal abortions in Poland — violates a constitutional provision that calls for protecting the life of every individual.

The court agreed with the lawmakers that an abortion predicated on the health of a fetus constituted illegal discrimination. The opinion approved by 11 of the government-controlled court's 13 judges said that ending a pregnancy due to birth defects amounted to eugenics — a 19th century notion of genetic selection that German Nazis applied in experiments.

Health Ministry figures for 2019 show that most of the 1,110 legal abortions performed in Poland last year were due to fetal genetic defects like Down syndrome, or to physical defects.