HONG KONG, July 15 (Xinhua) -- The Liaison Office of the Central People's Government in the Hong Kong Special Administrative Region (HKSAR) on Wednesday strongly condemned the signing of the so-called "Hong Kong Autonomy Act" into law by the United States and firmly opposed the U.S. gross interference in Hong Kong affairs.

The liaison office said in a statement that the Law of the People's Republic of China on Safeguarding National Security in the HKSAR was adopted by a unanimous vote by the Standing Committee of the National People's Congress and promulgated in the HKSAR on June 30.

In recent days, various sectors of Hong Kong society and the general public have expressed by different means their support for the national security law for Hong Kong, expecting Hong Kong to end the year-long social unrest and get back on track soon under the protection provided by the law, it noted.

The United States, in disregard of China's repeated representations and objections, maliciously smeared the national security law for Hong Kong and persisted in signing the so-called "Hong Kong Autonomy Act" into law, the statement said.

This is a gross interference in China's internal affairs and an outrageous desecration of the common will of the 1.4 billion Chinese people including Hong Kong compatriots, it added. "We express firm opposition to and strong condemnation of it."

Since the social unrest last year, Hong Kong has been facing the gravest situation after its return to the motherland as radicals committed violent and terrorist activities and anti-China forces blatantly advocated "Hong Kong independence," the statement said, adding that law and order in Hong Kong was seriously jeopardized and the interests of Hong Kong residents were harmed.

The statement said the role of the United States in the unrest is apparent and some U.S. politicians also know the truth well.

It is in line with the sovereignty principle and the international practice for China to enact a law to safeguard national security, end the chaos and close legal loopholes in Hong Kong, which is a special administrative region of China, the statement said.

The U.S. interference and threats were bullying and unreasonable, the statement said.

The United States has reaped enormous interests in Hong Kong and its so-called economic sanctions will only damage its own interests, rather than having real influence on Hong Kong, the statement said.

As national security is under protection, Hong Kong will return to stability and make new progress, guaranteed by "one country, two systems," the Basic Law and the support of the nation, the statement said.

No external force can undermine China's resolve and confidence to safeguard national sovereignty and security and Hong Kong's long-term prosperity and stability, the statement said.