China appoints hardliner Zheng Yanxiong as its top representative in Hong Kong

Zheng was among the officials sanctioned by the US for undermining Hong Kong's autonomy and freedoms

China has appointed the head of the national security office in Hong Kong as its top representative officer in Hong Kong - a sign that Beijing will tighten its control over the city.

Zheng Yanxiong, 59, replaces another hardliner, Luo Huining, 68, as head of Beijing's top representative office in Hong Kong, the State Council said in a notice.