South Korean Navy says latest exercise is aimed at mastering the allies’ response to a North Korean ballistic missile launch.

The drill on Sunday was conducted in international waters between South Korea and Japan and brought together destroyers equipped with Aegis radar systems from the three countries, the South Korean Navy said.

A naval officer said the exercise focused on practising procedures to detect and track a computer-simulated ballistic target and share related information.

North Korea fired its latest Hwasong-18 missile, which Pyongyang describes as the core of its nuclear strike force, off its east coast on Wednesday in what it said was a “strong practical warning” to its adversaries.

The launch followed heated complaints from North Korea in recent days, accusing US spy planes of flying over its exclusive economic zone waters, condemning a recent visit to South Korea by a US nuclear-powered cruise missile submarine and promising to take steps in reaction.

Seoul, Tokyo and Washington denounced the ICBM launch, saying it constituted a “clear, flagrant violation” of multiple United Nations Security Council resolutions and posed “a grave threat to peace and stability on the Korean Peninsula and beyond”.

The South Korean Navy said Sunday’s joint drills “served as an opportunity to enhance our military’s response capabilities against ballistic missiles and improve security cooperation” between South Korea, Japan and the US.

“We will effectively respond to North Korea’s nuclear and missile threats with our military’s strong response system and the trilateral cooperation,” it added.

The US and its Asian allies have been working to improve their information-sharing system on North Korea’s missiles.

South Korea and Japan are independently linked to US radar systems but not to each other’s.