South Korea, the U.S. and Japan are currently conducting a combined defense exercise against ballistic missiles to deter and respond to North Korea's nuclear and missile threats.

The defense ministry announced on Monday that the South Korean and U.S. navies and the Japanese Maritime Self-Defense Forces are carrying out the drill in international waters off the East Sea.

The training to enhance the three countries' proficiency in missile detection and tracking under a North Korean ballistic missile provocation scenario is a response and warning following Pyongyang's firing of the new “Hwasong-18” solid-fuel intercontinental ballistic missile(ICBM) last week.

South Korea's Yulgok Yi Yi Sejong the Great-class Aegis destroyer, the U.S. Benfold Arleigh Burke-class destroyer and a Japanese Atago-class destroyer have been deployed to participate in the exercise.

Another government source said the three sides plan to conduct such training on a regular basis regardless of provocations by Pyongyang.

Last Friday, South Korea, the U.S. and Japan resumed their defense trilateral talks in Washington after a three-year hiatus, agreeing to hold joint missile defense and anti-submarine warfare drills regularly.