US Secretary of State Rex Tillerson, unlike Secretary of Defence James Mattis, will visit China as well as Japan and the Republic of Korea during his tour of East Asia from Wednesday.

And since Tillerson' tour kicks off at a time when China and the US are working closely on a possible meeting between President Xi Jinping and United States President Donald Trump, his visit has drawn much attention.

The US media have reported the two leaders are likely to meet in early April. Apparently, the two sides have narrowed their differences since Trump's conversation with Taiwan leader Tsai Ing-wen on the phone soon after taking office. Later Trump promised to abide by the one-China policy.