BEIJING • China has warned the United States that it will take "every necessary measure" to protect its interests after a top White House adviser warned that Washington might revoke Hong Kong's special trading privileges if the Chinese government enacts a national security law.

Taiwan's President Tsai Ing-wen has also indicated Taipei may revoke the special status it extends to Hong Kong, in a move that is likely to anger China and will make it harder for Hong Kongers to visit and invest in the island.

China plans to impose legislation on Hong Kong that bans treason, subversion and sedition, officials said in response to months of massive protests in the financial hub.

US National Security Adviser Robert O'Brien warned on Sunday that China's new law could cost Hong Kong the preferential trading status it enjoys with the US, the world's largest economy.

But China's Foreign Ministry yesterday said the US has "no right to criticise and interfere".

"What laws, how, and when Hong Kong... should legislate are entirely within the scope of China's sovereignty," said Foreign Ministry spokesman Zhao Lijian.

"If the US insists on hurting China's interests, China will have to take every necessary measure to counter and oppose this," he added.

Beijing had already made "stern representations to the US", he said.

Hong Kong was handed back to China by Britain in 1997 under a "one country, two systems" framework valid for at least 50 years, which assures Hong Kong of freedoms such as those of expression.

The US treats Hong Kong differently from China in matters of trade and commerce, under the 1992 Hong Kong Policy Act, by exempting Hong Kong exports from tariffs imposed by Washington on Chinese goods under the US-China trade war.

Mr O'Brien's remarks came amid soaring tensions between Washington and Beijing - and only a day after Chinese Foreign Minister Wang Yi warned that the two countries seemed poised "at the brink of a new Cold War".

Ms Tsai, writing on her Facebook page late on Sunday, said China's proposed legislation was a serious threat to Hong Kong's freedoms and judicial independence, and that Taiwan would provide the people of Hong Kong with "necessary assistance".

Taipei deals with Hong Kong and Macau under rules that, for example, allow residents of the two Chinese cities to visit and invest in Taiwan much more easily than mainland Chinese.

Ms Tsai said if there were a "change in the situation" in Hong Kong, the Act laying out those rules could be revoked.

AGENCE FRANCE-PRESSE, REUTERS