"These serious illegal actions trample on the rule of law in Hong Kong, undermine Hong Kong's social order and harm the fundamental interests of Hong Kong", the Hong Kong and Macao Affairs Office of the State Council, China's cabinet, said in a statement. "It is a blatant challenge to the 'one country, two systems' bottom line. We express our vehement condemnation against this".
The protests erupted last month when the authorities began considering amendments to a bill to allow Hong Kong to extradite suspects to jurisdictions with which it does not have an extradition agreement - which includes mainland China and Taiwan. After numerous clashes between the protestors and police the bill was suspended and Hong Kong's Chief Executive Carrie Lam publicly apologised for it.
The Hong Kong region has legal and economic systems different from mainland China. Hong Kong was returned to the country by the UK in 1997 on the basis of "one country, two systems" rule.
