South Korea, the United States and Japan kicked off major new military exercises on Thursday, Seoul's Joint Chiefs of Staff said, as the allies seek to counter growing threats from Pyongyang.
The drills, dubbed "Freedom Edge", will focus on ballistic missile and air defences, anti-submarine warfare and defensive cyber training, among other areas, the JCS said in a statement.
The three countries' leaders held a summit last year and agreed to conduct drills every year to demonstrate unity in the face of North Korea's nuclear threats and China's rising regional influence.
Similar combined military exercises in the past have infuriated Pyongyang, which sees them as rehearsals for an invasion.
The drills, which are set to wrap up Saturday, will involve the nuclear-powered aircraft carrier USS Theodore Roosevelt, Japan's guided-missile destroyer JS Atago, and Seoul's KF-16 fighter jet, among other assets.
Ahead of the drills, South Korean President Yoon Suk Yeol visited the USS Theodore Roosevelt, after it arrived in the southern port of Busan on the weekend.
The United States is one of only two countries with aircraft carriers that use nuclear energy for propulsion, enabling them to operate for extended periods without needing to refuel.
The ship's arrival prompted an angry response from North Korea, which said it was opening "all possibilities of demonstrating (our) overwhelming and new deterrent force."
Thursday's announcement from Seoul came hours after North Korea claimed to have successfully tested its multiple-warhead missile capability.
