US President Joe Biden and his Chinese counterpart Xi Jinping began their virtual talks on Monday amid mounting tensions in the bilateral relationship.
"We have a responsibility to the world and to our people," Biden said at the start of the meeting. He added that "all countries have to play by the same rules of the road."
The two leaders traveled together when both were vice presidents and know each other well.
"I am very happy to see my old friend," Xi told Biden at the start of the meeting.
The Chinese leader told his US counterpart the two sides should improve communication.
A healthy and stable bilateral relationship is necessary for dealing with global challenges like climate change and COVID-19, he said, according to a report from Chinese state media.
"I stand ready to work with you, Mr. President, to build consensus, take active steps and move China-US relations forward in a positive direction,'' said Xi.
Biden calls for 'common sense guardrails'
Biden said that the two leaders must make sure the two nations' relations do not veer into open conflict, including by installing "common sense guardrails."
He promised to address areas of concern for Washington, including human rights and other issues in the Indo-Pacific region.
After the opening remarks, both leaders began private talks on a range of thorny issues that have raised tensions between the two sides.
Officials expect the meeting to stretch several hours. In the run-up to the meeting, the White House set low expectations, saying that no major announcements or even a joint statement were anticipated.
The United States and China, the world's biggest economies, disagree on a number of issues, including trade, technology and competition rules, Beijing's military posturing in the South China Sea and its attitude toward Taiwan, as well as human rights violations in Hong Kong and Xinjiang.
Taiwan to be high on the agenda
Chinese officials said Taiwan would be their top issue for the talks.
Beijing views the self-governing island as a Chinese province and has vowed to bring it under its control, even by force if necessary.
China has dispatched an increasing number of fighter jets near Taiwan, contributing to tensions and fears of a miscalculation triggering an unintended military conflict.
"The Taiwan issue concerns China's sovereignty and territorial integrity, as well as China's core interest," Chinese Foreign Ministry spokesperson Zhao Lijian said Monday.
"It is the most important and sensitive issue in China-US relations."
In the face of what Washington has described as Chinese aggression, the US has repeatedly signaled its support for Taiwan. But Washington is careful not to show it recognizes Taiwan, even though an act of Congress passed in 1979 requires the US to provide weapons to the island for self-defense.
The White House said Biden will abide by the longstanding US "One China" policy, which recognizes Beijing but allows informal relations and defense ties with Taipei.
