The United States believes China’s primary focus currently is its economy and that it is determined to work to stabilize bilateral relations with the United States, U.S. Deputy Secretary of State Kurt Campbell said on Wednesday.

Campbell told Washington’s Stimson Center think tank China needed to reassure investors and others that it has a plan for its economy and would not be looking to create frictions that could escalate in unpredictable and dangerous ways.

“It’s very hard for China to take certain steps without harming its own economy,” Campbell said. “And I think we now understand that economic performance is central right now to what is important to President Xi.”

Campbell was addressing questions about stepped up pressure China has put on U.S. allies and partners in the Indo-Pacific region, which has included run-ins with the Philippines over rival maritime claims in the South China Sea and increased military activity around Taiwan.

The U.S. and China have taken steps to reengage at high levels diplomatically after relations sank to their lowest point in decades, but serious frictions remain, including China’s support for Russia in its war in Ukraine, and worries that Beijing might act against Taiwan as Moscow did against Kiev.

“The hope will be that we’ll be able to settle on certain things that are necessary for the sustainment of the global economy, that are unexceptional with respect to national security,” Campbell said of the efforts in dialogue with China.

“Ultimately, that requires both strengthening, extending and also careful coexistence, and that’s really the nature of the diplomatic challenge that we have in front of us. It is one of the most difficult challenges in the history of American foreign policy.”

Campbell said he believed China had some anxieties about North Korea’s strengthened relations with Russia, and Washington was concerned about what Russia might provide Pyongyang in return for missiles and artillery shells the U.S. says it has provided to Moscow.

“What is Russia going to provide in exchange to North Korea? Hard currency? Is it energy? Is it capabilities that allow them to advance their nuclear or missile products? We don’t know, but we are concerned by that.”

Campbell said the U.S. has had no engagement with North Korea for years and it was hard to envisage when this might resume.

He said China and North Korea’s support for Russia in Ukraine would be discussed “in full” at next month’s NATO summit, but stressed that no new mission in the Indo-Pacific on the part of the U.S.-led Western alliance was in the offing.

On China’s pressure on the Philippines, Campbell, who met the secretary-general of the 10-member Association of Southeast Asian Nations, Kao Kim Hourn, in Washington on Monday, said ASEAN should “send an unmistakable message about concerns with respect to provocations in what is clearly the Philippines’ waters.”