Rex Tillerson

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

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 to his remarks. Beijing has called repeatedly for steps to reduce tensions.

Chinese Foreign Minister Wang Yi said North Korea could suspend its nuclear and missile activities in exchange for a halt in joint U.S.-South Korea military drills, a proposal swiftly shot down by U.S. Ambassador to the United Nations, Nikki Haley, who said Washington has to see “some sort of positive action” from North Korea before it can take leader Kim Jong Un seriously.

Tillerson’s comments in Seoul that “all of the options are on the table,” including possible military action, are likely to be deeply disconcerting to Beijing, which fears that a collapse of Kim’s regime would send waves of refugees into northeastern China and allow South Korean and American forces on its border.

China has agreed reluctantly to U.N. Security Council resolutions sanctioning North Korea, while calling for renewed dialogue under the Beijing-sponsored six-nation format that broke down in 2009.

China last month banned imports of North Korean coal, curtailing a source of foreign currency for Kim.