Foreign Ministry spokesman Zhao Lijian said on Wednesday that the national security legislation for Hong Kong is purely China's internal affair, which allows no foreign interference.

"China has to take necessary countermeasures in response to any such erroneous practice," Zhao said at a press conference in Beijing.

He made the remarks after US President Donald Trump said on Tuesday that the US is working on a strong response to China and it would be announced before the end of the week.

Hong Kong is a special administrative region that belongs to China and the central government is responsible for upholding national security in the country, Zhao said, reiterating the Chinese government's determination in implementing the "one country, two systems" policy, safeguarding national sovereignty, security and development interests, and opposing external interference in Hong Kong affairs.

Zhao also said that China fully agreed and highly appreciated Russian Foreign Minister Sergey Lavrov's positive comments after Lavrov said that recent statements by US officials about Hong Kong are "filled with a sense of superiority and a sense of impunity".

"The problems, which they are stirring up around Hong Kong, are related to China's domestic affairs, and we view them this way," Lavrov was quoted by Russian state news agency Tass as saying on Tuesday.

"Lavrov's remarks fully reflected the high level of China-Russia relations," Zhao said, adding that the two countries have been firmly supporting each other, especially on issues concerning their core interests.

The China-Russia Comprehensive Strategic Partnership of Coordination for a New Era has maintained sound and stable development under the guidance of leaders in both countries, he added.