SEOUL, South Korea (AP) — North Korea said Monday that leader Kim Jong Un observed test-flights of hypersonic missiles and underscored the need to bolster the country’s nuclear war deterrent, as the country dials up weapons displays ahead of its major political conference. North Korea reported on the drill a day after its neighbors said they detected multiple ballistic missile launches and accused the North of carrying out provocations. The tests came just hours before South Korean President Lee Jae Myung departed for China for a summit with President Xi Jinping.