China will not subjugate its national interests, Adm. Sun Jianguo told a regional defense forum in Singapore, even as he painted a picture of a country willing to cooperate on matters including the disputed South China Sea.

"China strives to play a constructive role in international affairs with an objective and impartial position and will never depend on or subjugate itself to any external forces," Sun said at the Shangri-La Dialogue, a day after U.S. Defense Secretary Ash Carter used his address at the forum to single out China as a source of instability.

The two speeches represented a toning down of the rhetoric from last year's forum, where former U.S. Defense Secretary Chuck Hagel got into a public spat with a Chinese general. That's even as tensions in the South China Sea have risen, with China parking weapons on a reclaimed reef and warning ships and planes from other countries away from the area. The U.S. has stepped up its patrols of the waters.