The sentencing of Jimmy Lai is reasonable and lawful, and allows no interference, Foreign Ministry spokesman Lin Jian said on Monday, after the High Court of the Hong Kong Special Administrative Region sentenced Lai to 20 years in prison.

Lai is a Chinese citizen, as well as the mastermind and a participant in a series of anti-China activities aimed at destabilizing Hong Kong, Lin told a regular news conference.

Lai's behavior seriously threatened the bottom line of "one country, two systems", jeopardized national security, undermined the prosperity and stability of Hong Kong, and harmed the well-being of Hong Kong residents, Lin said.

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Hong Kong is ruled by law, and its judiciary is fulfilling its duty to safeguard the authority of the law and national security, Lin said.

The central government firmly supports the Hong Kong SAR in following the law to safeguard national security and punish crimes that jeopardize national security, he also said.

"We urge certain countries to respect China's sovereignty and the Hong Kong SAR's rule of law, and refrain from making irresponsible remarks on the SAR's judicial proceedings," Lin said, adding that they should avoid interfering in Hong Kong's judicial matters or meddling in China's internal affairs in any form.