The United States has no right to meddle in legislation for the Hong Kong Special Administrative Region, and China will take any countermeasures necessary if the US insists on undermining the country's interests, Beijing said on Monday.

China is firmly opposed to "the noises some US politicians have made" over the draft decision on national security legislation in the SAR that was submitted to the third session of the 13th National People's Congress for deliberation, said Foreign Ministry spokesman Zhao Lijian.

The country has made solemn representations to the US in this regard, Zhao said at a daily news conference, after White House National Security Adviser Robert O'Brien told NBC's Meet the Press that the US may impose sanctions on China if it goes through with the legislation.

Hong Kong belongs to China, and legislation for the special administrative region is an issue totally within China's sovereignty, Zhao said.

No country allows activities that jeopardize its national security in its own territory, Zhao said. He added that only the national legislature has lawmaking power on issues concerning national security in any country.

The US, which "has gone to great lengths to protect its own national security by making dozens of laws", is using a double standard by "flagrantly interfering" in China's national security legislation, Zhao said.

Also, the draft legislation for Hong Kong, targeting "a tiny minority" of activities, such as those that aim to break up the country, will not affect the SAR's high degree of autonomy and Hong Kong residents' rights and freedoms, the spokesman said.

In contrast, it will improve Hong Kong's legal system, ensure a more stable social order and a better legal and business climate for the city, and help to achieve its long-term stability, Zhao said.

The legal basis for the Chinese government to govern Hong Kong is China's Constitution and the Basic Law of the Hong Kong Special Administrative Region of the People's Republic of China, instead of the Sino-British Joint Declaration, he said.

British rights and obligations, as outlined in the declaration, were completed when China resumed sovereignty over Hong Kong in 1997, and there is no legal basis for the US to cite the declaration and make irresponsible remarks over Hong Kong affairs, Zhao said.

Extensive violence proves the urgent need for national security legislation in Hong Kong, the special administrative region's Secretary for Security John Lee Ka-chiu said in a statement on Monday.

Noting that some people had displayed banners to advocate "Hong Kong independence" during Sunday's protest, Lee was quoted as saying in the statement: "Terrorism is growing in the city and activities that harm national security, such as 'Hong Kong independence', become more rampant."

"In just a few months, Hong Kong has changed from one of the safest cities in the world to a city shrouded in the shadow of violence," he said in the statement, adding that national security laws were needed to safeguard the city's prosperity and stability.

The Hong Kong SAR government's top officials and lawyer groups in the city strongly condemned violence during the illegal protests on Sunday.

Willy Fu Kin-chi, a law professor at Beijing Jiaotong University, said some foreign politicians' criticism of the proposed national security law was "unfair, unreasonable, and a double standard".

The vice-chairman of the Hong Kong Legal Exchange Foundation said some Western politicians tend to bully or unnecessarily interfere in other nations for the purpose of political or economic gains.

The West has an ideological bias regarding China, Fu said.