Brunei, Malaysia, Indonesia, the Philippines and Vietnam are all in dispute with the superstate over their territorial claims in the disputed South China Sea.
'That was unexpected, but I feel very fine, ' Trump said. The Chinese regime has responded with import tariffs on USA goods.
The US vice president's latest comments follow a major speech in October in which he flagged a tougher approach by Washington toward Beijing, accusing China of "malign" efforts to undermine US President Donald Trump and reckless military actions in the South China Sea.
A U.S. official told reporters that Pence was "currently having a "pull-aside" with the Taiwanese head of delegation to APEC Morris Chang".
Xi also defended his country's massive "Belt and Road" infrastructure initiative amid attacks that it is akin to "chequebook diplomacy" to further Chinese interests in the region.
In his closing comments, Mr O'Neill said Apec would try to ensure "free and open trade" in the region by 2020.
Xi gave no indication of giving in on some key USA demands, including an end to technology transfer, support for state-run enterprises, and giving up on its Made in China 2025 plan to lead the world in key industries. "Harassment will only strengthen our resolve".
Pence also met with Australian Prime Minister Scott Morrison.
The APEC summit in Papua New Guinea of leaders from 21 countries across the region has developed into a tussle for influence between an increasingly assertive China and a more withdrawn US.
Xi criticised "America First" trade protectionism and stressed that global trade rules should not be applied "with double standards or selfish agendas".
In contrast to Trump, Xi arrived two days before the summit, opening a new road and a school in Port Moresby and holding talks with Pacific Island leaders.
"History has shown that confrontation ― whether in the form of a cold war, hot war or trade war ― will produce no winners", he said.
"Mike, will you be my running mate?" he asked, turning to the vice president and asking him to stand and raise his right hand, which he did.
During a November 13 speech ahead of the Asean summit, Chinese Premier Li Keqiang said his country hopes the ongoing negotiations between Asean and China "will be finished in three years' time" - making it clear that Beijing is in no rush to enter any binding multilateral agreement anytime soon.