- Chinese leader Xi Jinping has outlined his "four red lines" to US President Joe Biden.
- The hot-button issues concern democracy and China's development.
- Xi's comments came two months ahead of President-elect Donald Trump's inauguration in January.
It will be another two months before US President-elect Donald Trump takes office, but China is already setting boundaries between the two countries.
On Saturday, Chinese leader Xi Jinping outlined his "four red lines" in US-China ties at a meeting with US President Joe Biden.
The four hot-button issues are Taiwan, democracy and human rights, China's path and system, and the country's rights to development.
"They must not be challenged," said Xi, according to a statement after the two leaders' meeting on the sidelines of the 31st APEC Economic Leaders' Meeting in Lima, Peru.
"These are the most important guardrails and safety nets for China-US relations," said Xi.
Of the four issues, Taiwan is the most sensitive issue between the two countries, as Xi has repeatedly said over the years.
Beijing claims Taiwan as its territory and has said recently that it will never commit to renouncing the use of force over the island. The area is strategically important to the US as the world's semiconductor chip-producing hub and a key security hub.
But Trump's presidency is already raising risks for Taiwan.
In June, Trump told Bloomberg Businessweek that Taiwan should pay the US for defense.
Trump could start his trade war on his first day
Xi's comments came amid concerns that the world's two largest economies are set to head into conflict after Trump takes office on January 20.
The incoming American president has already nominated Florida Sen. Marco Rubio, a China hawk, as Secretary of State. Trump has also threatened to hit China with tariffs of 60%.
Despite signs that the two superpowers could be headed for rockier times, Xi and Biden sought to strike a conciliatory tone on bilateral ties during their Saturday meeting.
The two leaders "stressed the importance of responsibly managing competitive aspects of the relationship" as well as preventing conflict and maintaining open lines of communication, according to a White House readout of the meeting.
Even so, Trump's impending presidency is likely to bring about fresh uncertainties, starting with trade.
"Trump means what he says when it comes to tariffs," wrote Josh Lipsky, the senior director at the Atlantic Council's GeoEconomics Center, in a note last week.
Lipsky expects Trump to start his new trade war during his first day on the job by trying to revive the trade deal he signed with China in January 2020.
China committed to purchasing $200 billion of American goods over two years, including $32 billion in agriculture products. The deal expired at the end of 2021 with the Chinese not meetingtheir commitment, said Sarah Bianchi, then the deputy US trade representative, in February 2022.
Trump is likely to try to revive the trade deal once he takes office as a "useful starting point" before the new tariffs come into effect, wrote the Atlantic Council's Lipsky.
Lipsky said he doesn't expect Trump to impose 60% tariffs on Chinese imports to the US across the board. But he wrote that there will be "real and tangible new tariffs," the effects of which will spill over to the global economy.