US and South Korea conduct joint military drills amidst North Korean missile testing.

South Korean and US troops are conducting their largest amphibious landing drills in years, involving a US amphibious assault ship, the USS Makin Island, which docked at a naval base in Busan on Wednesday. The drills, called Ssangyong, will last until April 3 and involve 12,000 sailors and marines from both countries, as well as 30 warships, 70 aircraft, and 50 amphibious assault vehicles. The exercises come a day after North Korea tested four long-range cruise missiles and are aimed at building "muscle memory" to respond to a crisis if needed.