Hong Kong police arrested five people Thursday, on suspicion of conspiring to publish "seditious material" with the intent of inciting public hatred towards the Chinese-ruled city's government among children.
Those arrested were members of a speech therapists' union who produced books for children with wolves and sheep as characters in stories, Steve Li, a senior superintendent of the national security department, told a news conference Thursday.
Two men and three women aged between 25 and 28. They did not identify them, police said.
Download the NBC News app for breaking news and politics
They were arrested under a colonial-era law targeting sedition, which had been rarely used before the anti-government protests began in the former British colony.
First convictions under the law can carry a maximum penalty of two years in prison, police said.
Li said the content of the books were "stirring up hatred" towards the government and "inciting violence."
"They are using children's cartoons to simplify and beautify illegal behavior on political issues," he said. "For example, the evil acts of thugs during the 2019 protests and painting the 12 Hong Kong fugitives as heroes. They are poisoning our children."
Li urged parents and shops that stock the books to throw them away.
The arrests were the latest involving suspected critics of Hong Kong's government that have raised fears about the shrinking space for dissent since Beijing's imposition of a sweeping national security law in June last year to put an end to the pro-democracy protests.
Authorities have denied any erosion of rights and freedoms in Hong Kong - which returned to China in 1997 under a "one country, two systems" formula aimed at preserving its freedoms and role as a financial hub - but say China's national security is a red line.
Security officials have said law enforcement action is based on evidence and has nothing to do with an individual's political stance, background or profession.