China’s ambassador to the United States held a rare meeting with the top U.S. defense official on Asian affairs at the Pentagon on Wednesday, Reuters reported.

A brief Pentagon statement said Chinese Ambassador Xie Feng discussed defense relations and “a number of international and regional security issues” during talks with Eli Ratner, the US deputy defense secretary.

“Ratner also emphasized the Department’s commitment to maintaining open military-to-military lines of communication between the United States and the PRC,” Pentagon spokesman Lt. Col. Martin Mainers said, using an abbreviation for China’s official name.

According to Meiners, the negotiations lasted about 90 minutes.

China’s embassy in Washington did not immediately respond to Reuters’ request for comment.

With U.S.-China relations at an all-time low over national security issues including Taiwan, U.S. bans on advanced technology exports and China’s state-owned industrial policy, Washington is trying to forge ties between the world’s two largest economies.

US Treasury Secretary Janet Yellen visited China earlier this month, and climate envoy John Kerry is expected to visit next week.

Last month, Secretary of State Anthony Blinken visited Beijing, the first trip by a US secretary of state to China since 2018.