U.S. Secretary of State Rex Tillerson has arrived in Beijing for his first face-to-face talks with Chinese leaders expected to focus on North Korea’s nuclear programme, trade and South China Sea territorial disputes.

Mr. Tillerson’s visit followed his remarks in South Korea on Friday in which he warned that pre-emptive military action against North Korea might be necessary if the threat from their weapons program reaches a level “that we believe requires action.”

China, the North’s biggest source of diplomatic support and economic assistance, has yet to respond.

Chinese Foreign Minister Wang Yi, with whom Mr. Tillerson was due to meet on Saturday afternoon, warned last week that the North and Washington and Seoul were like “two accelerating trains” headed at each other, with neither side willing to give way.