Xi's remarks come after Trump tapped Taiwan supporters Marco Rubio and Mike Waltz for top spots in his administration.

It's another two months before US President-elect Donald Trump takes office, but China is already setting boundaries between the two countries. On Saturday, China's leader, Xi Jinping, outlined his "four red lines" in US-China ties at a meeting with US President Joe Biden.

Amid the countries’ jostle for power, Chinese President Xi Jinping and his American counterpart Joe Biden agreed that humans, not artificial intelligence, would make the final decisions on the use of nuclear weapons.