Chinese President Xi Jinping speaks next to his U.S. counterpart Donald Trump during a business leaders event at the Great Hall of the People in Beijing, China, on November 9, 2017.

China's President Xi Jinping told President Donald Trump in a phone call on Tuesday that the hard-earned easing of tensions on the Korean Peninsula must continue, Chinese state media reported.

Unity on the issue was extremely important, Xi said, according to Chinese state broadcaster CCTV.

Senior officials from 20 nations will gather in Vancouver on Tuesday for a summit on curbing North Korea's nuclear ambitions, in a bid to increase diplomatic and financial pressure on Pyongyang to scrap its missile and nuclear programs.