China's foreign ministry has warned Washington against challenging Beijing's sovereignty.
Donald Tsang is the most senior Hong Kong official to face a corruption trial.
It is seen as an effort to increase pressure on North Korea after the country's latest missile test.
The resignation that shook Hong Kong's media
Will North Korean killing derail ties with China?
Mystery of a Chinese tycoon's disappearance
Year of the Rooster prompts reflections on rural origins
The Chinese man trapped in India for half a century
Beijing's global gamble in era of Trump
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