Xi Jinping gave two cellphones to South Korea’s president, who asked how secure they were. “You can check if there’s a backdoor,” he said with a laugh.

The country’s new president rolled out the red carpet for China’s leader, Xi Jinping, and President Trump this week, but the superpower rivalry is making it harder to balance relations.

A preliminary tariff deal with President Trump called for a large investment in the United States, while China has warned Seoul not to side with Washington.

President Trump’s visit shows how the United States and China are vying for influence in Asia over trade, technology and the fate of Taiwan.

From Kuala Lumpur to Gyeongju, President Trump is casting himself as a deal-maker and peace negotiator, while a wary region looks for tariff relief and steadier ties.