China on Thursday pledged to review the electoral system of Hong Kong at its upcoming parliament, in the latest move that would further threaten democracy and human rights in the special administrative region.

At the National People's Congress last year, China passed a resolution to introduce a national security law to crack down on what Beijing views as subversive activity in Hong Kong. The controversial legislation was enacted in late June last year.

It remains unclear how the Chinese Communist-led government will change the electoral system, but foreign affairs experts warn that the mainland would certainly try to tighten its grip on Hong Kong.

In Hong Kong, the legislative election is slated to be held in September, while the semiautonomous city's chief executive is expected to be selected next year.

Under China's "one country, two systems" policy, the former British colony was promised it would enjoy the rights and freedoms of a semiautonomous region for 50 years following its return to Chinese rule in 1997.

This year's session of China's parliament will be held for seven days from Friday.