Beijing’s top political office in Hong Kong has called protesters a “political virus” and said the semi-autonomous city will never be calm until “poisonous” and “violent” black-clad demonstrators are eliminated. The warning on Wednesday by China’s Hong Kong and Macao Affairs Office (HKMAO) said the central government in Beijing would not sit idly by with “this recklessly demented force” in place, referring to the protest movement which has shaken Hong Kong since last June and sometimes drawn millions to the street. It said the protesters and their oft-used mantra of “if we burn, you burn with us” were a “political virus”, and that the movement’s organisers wanted to “drag Hong Kong off a cliff”. It said that while many Hong Kongers had sympathy and understanding for them, “the more sympathisers the tyrants have, the greater price Hong Kong will pay”. The HKMAO statement comes amid a ratcheting up of rhetoric from Beijing towards protesters in Hong Kong and a crackdown on pro-democracy leaders before elections in September. More than 7,000 protesters have been arrested since June, and recent hardline tactics, including the mass arrests of protest figures, have drawn international criticism and accusations Beijing is using the pandemic as a cover to “turn the screws on Hong Kong”. The HKMAO labelled the protest movement as black-clad violence which openly challenged the “one country, two systems” principle, trampled on the rule of law, disrupted the social order, damaged property, business, and Hong Kong’s reputation, and endangered lives. Hong Kong’s economy recorded its deepest ever contraction this quarter, dropping 8.9% year on year. The statement said there were several factors including the coronavirus pandemic, but “the biggest scourge in Hong Kong comes from within”. “It can be said the forces of black violence are destroying the foundation of Hong Kong’s prosperity and stability,” the statement said. It said the central government had responsibility for safeguarding national security and the constitutional order in Hong Kong, and called for the urgent implementation of long-shelved national security laws. As Hong Kong relaxes strict Covid-19 pandemic measures, some protests have started again, mostly small groups of people gathering in shopping malls to sing. Police have reportedly enforced bans on public gatherings and used pepper spray to disperse people. Applications for larger marches have been denied. The HKMAO accused protesters of ignoring epidemic prevention laws to protest on Labour Day, and attempting to restart “street warfare”, citing police reports of discovering bomb-making materials and the arrest of a 15-year-old demonstrator for throwing a petrol bomb on 1 May. The pathology-themed statement repeated rhetoric last seen in November, when the protesters were denounced in Chinese state media as an “infection” and a “malignant virus”. Social media users associated with the protests described it as intimidating language, and joined observers noting its similarity to Communist party (CCP) discourse about Xinjiang and the detention of Uighurs. Human Rights Watch (HRW) told the Guardian the rhetoric was “chilling and disturbing” and indicated the CCP intended “to assume greater direct control over Hong Kong”. “It is regrettable that the Chinese government seems to be increasingly inflexible in dealing with its population from Xinjiang to Hong Kong, using the only tool it has in disposal: a crackdown,” said HRW senior China researcher, Maya Wang. “The Chinese government can still reverse its course by addressing the many grievances people in Hong Kong have, namely, the erosion of freedoms and autonomy, but unfortunately it is going down the wrong path of heightening tensions.” The HKMAO, the director of which was replaced in February by the hardline party official Xia Baolong, has been increasingly interventionist in Hong Kong affairs. Last month it was accused – alongside Beijing’s liaison office in Hong Kong – of a “flagrant breach” of the agreement struck between Britain and China in 1997, when Hong Kong was returned to Chinese control. Under the agreement, Hong Kong was promised a high degree of autonomy for 50 years. However, the offices denied accusations they were bound by sections of Hong Kong’s mini-constitution, the Basic Law which prevented central government interference in local affairs, saying “a high degree of autonomy is not complete autonomy” and the right to self-rule was “authorised by the central government”. On Tuesday, pro-Beijing politicians formed the Hong Kong Coalition, calling for adherence to the one country, two systems principle. The HKMAO praised the group’s formation. Additional reporting by Lillian Yang