President Joe Biden and Chinese counterpart Xi Jinping held "candid" phone talks on Thursday, with Xi warning the US leader not to "play with fire" on Taiwan, according to Chinese state media.
The virtual summit lasting over two hours took place as Beijing and Washington increasingly risk open conflict over the self-ruling island, which China considers part of its territory.
"Those who play with fire will eventually get burned," Xi was quoted as telling Biden in reference to Taiwan, according to the state-run Xinhua news agency - using the same language he had employed when they spoke last November.
"I hope the US side fully understand that," Xi told Biden. "The position of the Chinese government and people on the Taiwan issue is consistent,'" Xi was quoted as saying.
"It is the firm will of the over 1.4 billion Chinese people to firmly safeguard China's national sovereignty and territorial integrity."
While this was Biden's fifth talk with Xi since becoming president a year and a half ago, it's getting hard to mask deepening mistrust between the two countries amid a trade war and tensions over Taiwan.
The latest flashpoint is a possible trip by Biden ally and speaker of the House of Representatives, Nancy Pelosi, to the island, which has its own distinct democratic government.
White House National Security Council spokesman John Kirby had said "tensions over China's aggressive, coercive behaviour in the Indo-Pacific" would be high on the agenda — using the US administration's term for the Asia-Pacific region.
Although US officials frequently visit Taiwan, separated by a narrow strip of water from the Chinese mainland, Beijing considers a Pelosi trip as a major provocation.
She's second in line to the US presidency and given her position may travel with military transport.
Washington will "bear the consequences" if the trip, which Pelosi has yet to confirm, goes ahead, China warned on Wednesday.
General Mark Milley, chairman of the US joint chiefs of staff, told reporters that if Pelosi asks "for military support, we will do what is necessary to ensure a safe, safe conduct of their business."
And the dispute around Pelosi is the tip of an iceberg, with US officials fearing that Xi is mulling use of force to impose control over democratic Taiwan.
Once considered unlikely, an invasion, or lesser form of military action, is increasingly seen by China watchers as possible - perhaps even timed to boost Xi's prestige when he moves later this year into a third term.
Biden's contradictory comments on whether the United States would defend Taiwan - he said in May that it would, before the White House insisted there was no change in the hands-off "strategic ambiguity" policy - have not helped the tension.
Biden prides himself on a close relationship with Xi going back years but - in large part due to COVID-19 travel restrictions - the two have yet to meet face-to-face since he took office.
According to the White House, Biden's chief goal is to establish "guardrails" for the two superpowers.
This is meant to ensure that while they sharply disagree on democracy, and are increasingly rivals on the geopolitical stage, they can avoid open conflict.
"He wants to make sure that the lines of communication with President Xi on all the issues, whether they're issues again that we agree on or issues where we have significant difficulty with - that they can still pick up the phone and talk to one another candidly," Kirby said.
Where to place the guardrails, however, is challenging amid so many unresolved disputes, including a simmering trade war begun under Donald Trump's presidency.
Asked whether Biden could lift some of the 25 per cent import duties placed on billions of dollars of Chinese products by Trump, Kirby said there was still no decision.
"We do believe... that the tariffs that were put in place by his predecessor were poorly designed. We believe that they've increased costs for American families and small businesses, as well as ranchers. And that's, you know, without actually addressing some of China's harmful trade practices," Kirby said. But "I don't have any decision to speak to with respect to tariffs by the president. He's working this out."
Agence France-Presse