In a clear warning to rising pro-independence forces in Hong Kong, Beijing highlighted its "resolute opposition" to the movement as several young radicals won seats in the weekend's legislative council (LegCo) elections.
The election of the pro-independence candidates and "localists" - who put the interests of Hong Kong above those of the mainland - was unprecedented in a Hong Kong political system that has traditionally been dominated by pro-Beijing and pro-democracy factions, highlighting the disaffection Hong Kongers feel toward Beijing. China pledged a "One Country, Two Systems" policy in Hong Kong after its handover from the U.K. in 1997, a stance some say is fast eroding amid tightening control of political and civil liberties in the city.
In a statement from China's Hong Kong and Macao Affairs Office of the State Council, that was reported by the state-run Xinhua news agency on Monday, the mainland government highlighted that campaigning for Hong Kong's independence was against the constitution of China and the laws of Hong Kong.
The pro-independence movement is a threat to China's sovereignty and security, will damage the prosperity and stability of Hong Kong, and is counter to the fundamental interests of Hong Kong citizens, added Xinhua, citing the office's statement.
Among the localists who will take office on October 1 is 23-year-old Umbrella Movement student leader Nathan Law.
Law will be the youngest legislator in the 70-seat house, which includes 40 pro-establishment and 22 pro-democracy seats. Together, the opposition will make up more than a one-third veto bloc in the first major election since the 2014 protests.
The weekend's polls were the first elections since the Umbrella Movement protests of 2014, which were triggered by proposed changes to Hong Kong's electoral system, under which China planned to screen all nominees in the first direct election of the city's leader.