Biden to seek red lines in talks with Xi

US President Joe Biden said Sunday he will seek to establish "red lines" in America's fraught relations with Beijing in high-stakes talks with Chinese counterpart Xi Jinping.

The superpower sit-down will come on the sidelines of the G20 summit in Indonesia Monday, with leaders from the world's 20 largest economies holding their biggest gathering since the pandemic.

Biden said he was going into his first face-to-face with Xi as president "stronger", after his Democratic Party's unexpected success in midterm elections they had been forecast to lose heavily.

But the summit comes with Beijing and Washington's rivalry intensifying as a more powerful and assertive China tries to disrupt the US-led international order.

The world's two largest economies are at loggerheads on everything from trade to human rights in China's Xinjiang region and the status of the self-ruled island of Taiwan, and Biden said he expected "straightforward discussions" with Xi.

"I know Xi Jinping, he knows me," he told reporters in Phnom Penh where he met with Asian leaders before heading to the G20 on the Indonesian resort island of Bali.

"We have very little misunderstanding. We just got to figure out what the red lines are," Biden said.

White House officials say Biden will push China to rein in North Korea after a record-breaking series of missile tests fuelled expectations the reclusive regime will soon carry out its seventh nuclear test.

China is Pyongyang's main ally and while Biden is not expected to make demands, he will warn Xi that further missile and nuclear build-up would mean the United States boosting its military presence in the region -- something Beijing bitterly opposes.

"North Korea represents a threat not just to the United States, not just to (South Korea) and Japan but to peace and stability across the entire region," US National Security Advisor Jake Sullivan told reporters.

The talks will cast a long shadow over the first post-pandemic G20, a reunion that Russian President Vladimir Putin has pointedly opted to skip.

He is instead sending his Foreign Minister Sergei Lavrov, who arrived on Sunday evening.

Putin's invasion of Ukraine has made the trip to Bali logistically difficult and politically fraught, and while the war is not officially on the summit agenda, the conflict will dominate discussions.

Soaring energy and food prices have hit richer and poorer G20 members alike -- and both are directly fuelled by Putin's war.

There is likely to be pressure on Russia to extend a deal allowing Ukrainian grain and fertiliser shipments through the Black Sea when the current agreement expires on November 19.

At a minimum, Biden and his allies want the G20 to make it clear to Putin that nuclear war is unacceptable.

Even that once uncontroversial position is likely to be blocked by a mixture of Russian opposition and Chinese unwillingness to break ranks with its ally in Moscow or give Washington a win.

At a recent meeting with German Chancellor Olaf Scholz, Xi said a nuclear war could not be won and should never be fought.

Ryan Hass, a former director for China at the US National Security Council, said Xi "likely will not be as magnanimous in his meeting with Biden."

"He will not want to be perceived as satisfying a request from Biden, whether on Ukraine, nuclear use, North Korea, or any other issue," Hass told AFP.

G20 host Indonesia -- still careful not to favour either China or the United States -- is not confident that the leaders will be able to break the deadlock.

A string of G20 ministerial meetings, hosted by Indonesia in the run-up to the summit, have failed to agree on a final joint communique -- a procedural-sounding tradition that can be important in driving cooperation.

"Honestly, I think the global situation has never been this complex" said Indonesian government minister Luhut Binsar Pandjaitan on the eve of the summit.

"If eventually (the G20) leaders do not produce a communique, that's that, it's OK."