The Pentagon said on Tuesday that the United States, South Korea and Japan participated in a ballistic missile defense exercise off the coast of Hawaii last week and are continuing combined exercises focused on North Korea and China.

The three countries held such exercises for the first time since 2017, after relations between Seoul and Tokyo reached their lowest level in years amid new historical disputes spanning from 1910 to the Japanese occupation of the Korean peninsula from 1910 to 1945.

Conservative South Korean President Yoon Suk-yeol, who took office in May, has pledged to improve relations with Japan and deepen the alliance with the United States to better deter North Korea, including the expansion or resumption of joint exercises.

The Missile Warning and Ballistic Missile Search and Track exercise took place August 8-14 during the multinational Pacific Dragon exercises, demonstrating the three countries’ commitment to responding to the challenges posed by North Korea, maintaining common security and strengthening international rules-based rules. In a statement from the Pentagon, the system

Joint US-led missile defense measures have been a sensitive spot for China, which has economically retaliated against South Korea’s decision in 2016 to host the US Military Terminal High Altitude Area Defense (THAAD) battery.