US Secretary of State Antony Blinken on Monday said that China has pointed to Taiwan as a main area of disagreement.
Beijing claims the self-governing democracy, which buys weapons from Washington, and has not ruled out using force to seize it.
Blinken repeated that the United States does not support the independence of Taiwan and stood by its stance of maintaining the status quo.
"At the same time, we and many others have deep concerns about some of the provocative actions that China has taken in recent years going back to 2016," he said.
On another regional issue, Blinken said he spoke to China about using its influence over its ally North Korea, which has fired a volley of rockets and has rebuffed offers of talks with the Biden administration.
"All members of the international community have an interest in encouraging the DPRK to act responsibly to stop launching missiles, to start engaging on its nuclear programme," said Blinken, using the North's official name, the Democratic People's Republic of Korea.
"China's in a unique position to press Pyongyang to engage in dialogue and to end its dangerous behaviour."
