The Foreign Ministry on Monday announced sanctions on certain US Congress members, officials and heads of non-government organisations who "acted egregiously" on Hong Kong-related issues.

The announcement came three weeks after Washington put six mainland and Hong Kong officials on its sanctions list. They included the director for the Office for Safeguarding National Security in Hong Kong, Dong Jingwei, and Paul Lam, the Secretary for Justice.

Speaking at a daily press briefing, Foreign Ministry spokesman Guo Jiakun strongly condemned what he called "illegal and unilateral" sanctions.

"[These sanctions] are a grave interference of Hong Kong affairs and China's internal affairs. They also seriously violate the principles of international law, as well as the basic norms of international relations," he said.

Guo added Beijing will not allow US interference in Hong Kong affairs.

"Any wrong behaviour by the US will be met with resolute and reciprocal countermeasures from the Chinese side," he declared.