The U.S. and Chinese defense chiefs held talks for the first time in nearly 18 months on Tuesday, as the two sides seek to rebuild frayed military-to-military ties and manage the increasingly tense relationship.

U.S. Defense Secretary Lloyd Austin and Chinese Defense Minister Adm. Dong Jun spoke via video teleconference, the Pentagon said, with Austin emphasizing “the importance of continuing to open lines of military-to-military communication” between the two sides following a series of military engagements after U.S. President Joe Biden and Chinese leader Xi Jinping agreed last November to resume the military channels.

Pentagon press secretary Maj. Gen. Pat Ryder said the two had discussed Sino-U.S. defense relations as well as regional and global security issues of concern, with Austin voicing concern over China's moves in the South China Sea.