White House national security adviser Jake Sullivan met with Chinese Foreign Minister Wang Yi in Malta this weekend, Beijing and Washington said on Sunday, as the world’s two largest economies seek to stabilize troubled relations.

Both sides held “candid, substantive and constructive” talks during multiple meetings held Sept 16-17, according to separate statements from the White House and the Chinese foreign ministry published Sunday.

Sullivan’s meeting with Wang was the latest in a series of high-level discussions between US and Chinese officials that could lay the groundwork for a meeting of US President Joe Biden and Chinese President Xi Jinping later this year.

Sullivan last met Wang in Vienna in May.

China’s foreign ministry said both sides agreed to maintain high-level exchanges and hold bilateral consultations on Asia-Pacific affairs, maritime affairs and foreign policy.

The White House added that both sides “committed to maintain this strategic channel of communication and to pursue additional high-level engagement and consultations in key areas … in the coming months”.

Washington said Sullivan “noted the importance of peace and stability across the Taiwan Strait”, while Wang cautioned the United States that the Taiwan issue is the “first insurmountable red line of Sino-US relations”, according to the Chinese foreign ministry statement.

Biden this month expressed disappointment that Xi skipped a summit of Group of 20 leaders in India, but said he would “get to see him.” The next likely opportunity for Biden to hold talks with Xi is an Asia-Pacific Economic Cooperation (APEC) summit in San Francisco in November.

US Commerce Secretary Gina Raimondo, Secretary of State Antony Blinken and Treasury Secretary Janet Yellen have traveled to China this year to ensure continued communication between the two countries amid tensions that flared after the U.S. military shot down a Chinese surveillance balloon that traveled over the United States.

Biden and Xi last met in 2022 on the sidelines of a G20 summit on Indonesia’s resort island of Bali.