The United States’ top commander in the Indo-Pacific region spoke with his Chinese counterpart Monday night, according to three U.S. officials familiar with the planning, as the two superpowers try to rebuild military ties in an effort to avoid conflict.

Adm. Samuel Paparo, commander of U.S. Indo-Pacific Command, spoke with Gen. Wu Yanan, the commander of China’s Southern Theater, which is responsible for Beijing’s vast claims over the South China Sea. The call was the first time in years that the two regional military commanders have engaged in a formal conversation.