Pence said there would be no letup in President Donald Trump's policy of combating China's mercantilist trade policy and intellectual property theft that has erupted into a trade war between the two world powers this year.

He harshly criticized China's global infrastructure drive, calling many of the projects low quality and saddling developing countries with loans they can't afford.

Pence also announced the U.S. would be involved in a plan by its ally Australia to jointly develop a naval base in Papua New Guinea, where the summit is being held. China has been intensely wooing Papua New Guinea with aid and loans for infrastructure.

Xi, who spoke before Pence, said countries are facing a choice of cooperation or confrontation as protectionism and unilateralism spreads.

Xi expressed support for the global free trading system that has underpinned his country's rise to world's second-biggest economy after the U.S.

"Mankind has once again reached a crossroads," he said. "Which direction should we choose? Cooperation or confrontation? Openess or closing doors. Win-win progress or a zero sum game?"

Leaders of Pacific Rim countries that make up 60 percent of the world economy are meeting in the capital of Papua New Guinea for an annual Asia-Pacific Economic Cooperation summit.