The US and Chinese leaders have warned each other over Taiwan during a phone call that lasted more than two hours.
President Joe Biden told his Chinese counterpart, Xi Jinping, that the US strongly opposed any unilateral moves to change the island’s status.
But he added that US policy on Taiwan had not changed.
Beijing said Mr Xi had told Mr Biden to abide by the one-China principle, warning him that “whoever plays with fire will get burnt”.
Tensions over the issue have increased ahead of a rumoured plan for US House of Representatives Speaker Nancy Pelosi to visit Taiwan.
The state department says Ms Pelosi has not announced any travel, but China has warned of “serious consequences” if she were to proceed with such a visit.
Last week, Mr Biden told reporters “the military thinks it’s not a good idea”, but his White House has called Chinese rhetoric against any such trip “clearly unhelpful and not necessary”.
Ms Pelosi, who is next in line to the presidency after the vice-president, would be the highest-ranking US politician to travel to Taiwan since 1997.
During Thursday’s phone call, Mr Biden and Mr Xi also discussed arranging a possible face-to-face meeting, a senior Biden administration official said, describing the bilateral as “direct” and “honest”.
When Mr Biden was US vice-president he hosted Mr Xi during a visit to the US by the Chinese leader in 2015, but they have not met in person during Mr Biden’s presidency.
China sees Taiwan as a breakaway province that must become a part of the country – and has not ruled out the possible use of force to achieve this.
Under the one-China policy, Washington does not recognise Taipei diplomatically. But the US does sell weapons to the democratically self-governed island so that it can defend itself.