Chinese President Xi Jinping told U.S. President Donald Trump during a phone call on Monday that Taiwan's "return to China" is a key part of the post-war international order, state news agency Xinhua reported.

Current law requires elected officials to prove they renounced their former citizenship – which is impossible for those born on the mainland.

As China reportedly mulls a ban on Japanese seafood amid a standoff between the Asian neighbors, Taiwan's leader shows support for Tokyo, with his lunch.

China sent a letter to the United Nations vowing resolute self-defense if Japan “dared to intervene militarily in the Taiwan Strait,” as Beijing tries to rally international support for its position on the spiraling spat.

The de facto ambassador to Australia has warned that China’s coercive behaviour and military activity in the Pacific should ring alarm bells.

For years, China has threatened, cajoled and squeezed democratic Taiwan in an attempt to force it to fold without a costly war across the Taiwan Strait. Japan has mostly toed the US line of “strategic ambiguity”, rarely speaking out and officially saying that the dispute can be resolved through dialogue.

China is trying to impose economic costs on Japan for wading into the issue of Taiwan. But experts say the escalating dispute could ultimately hurt China too.

Japan's new leader prime triggered the dispute by saying Japan could intervene in a confrontation between China and Taiwan.