Hong Kong police arrested five trade union members and a court denied bail for four editors and journalists held on charges of endangering national security, as part of a widening crackdown on dissent in the city.

The five who were arrested are members of the General Association of Hong Kong Speech Therapists, according to local media reports.

The association published three children’s books that Li Kwai-wah, a senior superintendent of the national security department, said have seditious intent.

The books feature stories that revolve around a village of sheep that has to deal with wolves from a different village.

The sheep take action like going on strike or escaping by boat, according to the synopses published on the association’s website.

Mr Li said that the stories referenced the 12 Hong Kong activists who were arrested at sea while trying to flee the city, after most of them were charged in connection with massive anti-government protests in 2019.

There was also a story about wolves who are “cruel and try to occupy the area” where the sheep live, and try to kill them, he said.

The publishing of such books “brings hatred against the government and administration of justice, and (incites) violence to others,” Li said. He added that the books targeted children between the ages of 4 and 7.

Police confirmed they arrested two men and three women from a trade union, but did not identify them or the union.

Police said that they are suspected of conspiring to publish, distribute, display or copy seditious publications with the intent to incite hatred, violence and other non-law-abiding acts towards the Hong Kong authorities and the judiciary by the public, in particular young children.

Police said that also froze 160,000 Hong Kong dollars (20,600 US dollars) in assets linked to the union.

On Thursday, a Hong Kong court denied bail to four top editors and journalists from the now-defunct Apple Daily pro-democracy newspaper.

They were arrested Wednesday on charges of conspiracy to collude with foreign powers to endanger national security.

So far, eight former employees have been arrested.

Apple Daily ceased operations in June after 2.3 million US dollars in assets were frozen and police raided the newspaper’s offices, confiscating hard drives and laptops.

Following months of anti-government protests in 2019, Beijing last year imposed a sweeping national security law in the semi-autonomous city that critics say restricts freedoms promised to the former British colony that are not found on mainland China.

The law criminalises secessionism, subversion, terrorism and foreign collusion in the city’s affairs.

Since it was implemented, more than 100 pro-democracy supporters have been arrested and many others have fled abroad.