For years, the U.S. government has urged China to show "restraint" in pushing its claim on Taiwan and to drop military threats to bring the democratically governed island under its control. Now - some Chinese commentators say - the power of that long-held U.

Nicholas Burns, the U.S. ambassador to China, also said he was leaving his post with deep concerns about the future of relations with China.

Observers doubt the new US president will buy the world's largest island but his interest underlines its strategic importance President Donald Trump's claim that US ownership and control of Greenland is "an absolute necessity" has underlined the strategic importance of the world's largest island in terms of American missile defences and anti-submarine operations.