The national security advisers of the United States, Japan and the Philippines held their first joint talks Friday and agreed to strengthen their defense cooperation, as Washington and its partners reinforce their alliances to adapt to growing tensions over North Korea, China and Ukraine, White House national security adviser Jake Sullivan said. Sullivan said he and his Japanese and Philippine counterparts discussed the "turbulent regional security environment and how we can collectively work to enhance peace and stability” in areas including freedom of navigation and economic security.