Arson attacks against schools in the French-speaking region of Belgium have been linked to extremists protesting against mandatory sex education lessons for children.
The government has launched a terror investigation after eight attacks in Liege and Charleroi.
No one has claimed responsibility for the blazes.
But arsonists tagged school campuses with graffiti protesting the lessons, which address the topic of transgenderism in material aimed at children as young as nine.
The Evras programme has introduced four hours of mandatory classes to “give young people the necessary information to become enlightened adults” in schools.
In the guide, children aged nine to 11 are taught about how gender can differ from sex and “the importance of self-identification.”
Those aged 12 to 14 are taught about the body modifications needed to transition and services and support offered.
This year, around 100,000 students in the Wallonia-Brussels federation region will attend the training sessions.
It has prompted fears of “hypersexualisation” from six Islamic groups, who published an open letter arguing the lessons are a hindrance to parents’ freedom to “guide children’s education in accordance with their beliefs”.
Civitas, a French Catholic association, has demanded the classes be stopped.
At the vandalised schools, slogans such as “no Evras, otherwise you’re next” were spray-painted by the arsonists.
Belgium’s National Crisis Centre announced last week that anti-terrorism and intelligence services had been brought in to monitor the situation.
“These fires are inadmissible acts of terrorism,” Socialist education minister Caroline Desir said last week during a visit to one of the burnt schools near Charleroi.
Belgian prime minister Alexander De Croo said pandering to the protesters would be a step backwards as the country has offered sexual education for half a century.
“In a democracy like ours, we will never allow our schools to be a target,” he said.
“We live in a country of tolerance, and tolerance means we can have a debate, different points of view, but it can never lead to violence, especially in places frequented by our children.”
Despite the terror probe, 1,500 protestors gathered outside the central station in Brussels in a demonstration organised by Radya Oulebsir, a Muslim activist, and Alain Escada, a far-Right activist.
“Don’t touch our children”
The demonstrators chanted “don’t touch our children” as they were seemingly undeterred by being linked to an investigation into extremists.
Rumours about the nature of Eras have also been spreading on the internet and fuelling the protest.
Claims of alleged early sexualisation of children, incitement to pornography and discussions on gender change, masturbation and orgasms have been used to smear the scheme.
French rapper Rohff recently shared a petition against the “pedophilia and perversion” introduced by Evras and similar schemes.
“I would like to call on everyone to calm down and try once again to cut through the lies circulating about the Evras system,” Ms Desir said.
“No, it does not prepare a paedophile system. No, it doesn’t plan to make children want to change gender. No, it doesn’t plan to teach children how to engage in sexual activities.”
The Belgian government hired 150 experts to produce a 300-page guide to counter the perceived disinformation.
It is written in gender fluid French, scraping the usual grammatical genders associated with the language.
The experts suggest teachers start educating children between 13 and 15 years old about “gender transition” because that is when they are likely to start questioning their sex.