US President Joe Biden and his Chinese counterpart Xi Jinping made rival bids to win over Asia-Pacific allies at a summit in San Francisco Thursday, just a day after the two leaders met in a bid to reduce tensions between the superpowers.

"We're not going anywhere," Biden told business leaders attending the APEC (Asia-Pacific Economic Cooperation) summit in San Francisco as he tried to reassure the 21 member economies of US commitment to the region.

Biden said there would be regional and global benefits from his talks with Xi, a day after they met for the first time in a year at a villa outside the city and emerged pledging to avoid a dangerous rift.

They agreed to restore military-to-military links and Xi promised to curb production of the ingredients in China for the drug fentanyl, although disagreements over Taiwan remained broad.

"A stable relationship between the world's two largest economies is not merely good for those two economies but for the world," Biden said.

The only discordant note came when Biden told reporters on Wednesday that he still regarded Xi as a "dictator"

'Peace and security'

But despite the easing of tensions, Biden set out his stall that Washington was a better ally for many of the bloc's 21 member economies than an increasingly assertive Beijing.

He said Xi had asked him on Wednesday "why we are so engaged in the Pacific."

"I said it's because we're a Pacific nation. Because of us there's been peace and security in the region, allowing you to grow. He didn't disagree," said Biden.

Biden also had a three-way meeting with Japanese Prime Minister Fumio Kishida and South Korean President Yoon Suk Yeol, whom he hosted for a historic summit at Camp David in August.

Kishida and Xi had their first meeting in a year on the sidelines, with the Japanese leader voicing "serious concerns" over Chinese military activity in waters near Japan and Beijing's "collaboration with Russia".

He also demanded China lift its ban on Japanese seafood, imposed after Tokyo began releasing treated wastewater from the stricken Fukushima nuclear plant into the Pacific Ocean in August.

Competing for influence

China and the United States are competing for influence across the hugely dynamic area stretching from the coasts of Canada to Chile and across to Australia, Malaysia and Russia.

While China has been offering infrastructure and loans with its "Belt and Road" program, the United States is busily trying to strengthen alliances with trade and other agreements.

A big plank in that platform is the Indo-Pacific Economic Framework for Prosperity (IPEF) — a loose trade pact meant to bind together the United States and 13 like-minded democracies such as Australia and South Korea.

However, the IPEF has already hit the buffers because of US domestic political opposition that has held up a key element.

"We still have more work to do, but we made substantial progress," Biden said onstage with other leaders involved in the pact after they held talks to try to move things forward.

Pandas for peace?

Xi embarked on his own charm offensive at the APEC summit as he sought to win foreign investment in China's sputtering economy and call for an end to tensions with the United States.

"The region cannot and should not be an arena for geopolitical rivalry, still less should it be plunged into a new cold war or camp-based confrontation," he said in a written speech to CEOs.

Xi met Mexican President Andres Manuel Lopez Obrador, who frequently shuns international meetings, and Peru's interim President Dina Boluarte.

Obrador will huddle with Biden on Friday when the two men are expected to address fentanyl, some of which comes through Mexico on its way into the United States.

Xi also received a warm reception at a dinner in San Francisco on Wednesday with hundreds of US business leaders — reportedly including Tesla's Elon Musk and Apple's Tim Cook — who gave him several rounds of applause.

The Chinese leader then hinted at the dinner that he may deploy a form of soft power to improve ties — pandas.

Three of the popular big bears were sent back from Washington this month but Xi said China was considering a new batch as "envoys of friendship."