Open this photo in gallery: South Korea's President Yoon Suk Yeol speaks during a news conference with President Joe Biden in the Rose Garden of the White House in Washington on April 26.Andrew Harnik/The Associated Press Senior defense officials from South Korea, the United States and other nations on Tuesday warned North Korea over its nuclear ambitions and threats, vowing an unspecified collective response to any war-like aggression by the North toward its rival. Their joint statement came after a meeting in Seoul involving U.S. Secretary of Defense Lloyd Austin, South Korean Defense Minister Shin Won-sik and officials from 16...