The top ministers of Japan, the United States and Australia on Monday lambasted China's military buildup in the South China Sea and confirmed the importance of security cooperation in dealing with a territorial dispute in the waters.

Foreign Minister Taro Kono, U.S. Secretary of State Rex Tillerson and Australian Foreign Minister Julie Bishop also "welcomed" the fresh sanctions on North Korea that the U.N. Security Council adopted Saturday in response to Pyongyang's two long-range missile tests in July, according to a joint statement released following their talks.

On the South China Sea dispute, "the ministers voiced their strong opposition to coercive unilateral actions that could alter the status quo and increase tensions," the statement said, adding they urged claimants in the sea to refrain from "militarization of disputed features."