North Korea fires multiple ballistic missiles into Sea of Japan

North Korea fired off multiple ballistic missiles from its eastern coast on Monday, with at least two believed to have fallen into waters outside Japan’s exclusive economic zone.

The Defense Ministry in Tokyo said it had detected two separate launches. Both missiles appeared to have splashed down the Sea of Japan, outside the EEZ, which extends 200 nautical miles (370 kilometers) from Japan’s shores.

South Korea’s military said it had detected the firing of several ballistic missiles from the Pyongyang area, with the weapons flying more than 900 km.

“The South Korean military has stepped up its surveillance to prepare for additional launches and is maintaining an all-out readiness posture, while closely sharing relevant information with the United States and Japan,” it said in a release.

The launches come days after Seoul proceeded with a demining operation along the two countries’ heavily fortified border after three South Korean soldiers were injured in a land-mine blast it blamed on the North.

The North Korean Foreign Ministry said the South was attempting to “shift the blame for its own accident onto us,” and warned Seoul of retaliation if “even a millimeter” of its territory were violated.

Monday’s launches were North Korea’s fourth in about a month, coming just over a week after Pyongyang said it had tested an “intermediate-range strategic missile.” 

That test — part of an exercise overseen by North Korean leader Kim Jong Un — was conducted to train soldiers operating the “hypersonic strategic weapon system” and “evaluate the reliability, efficiency and mobility” of the North’s “war deterrent,” state-run media said.

It claimed that the missile flew 1,000 km — around 300 km further than initial estimates by Tokyo and Seoul.

The distance discrepancy of what the North said was an artificial intelligence-assisted missile has raised eyebrows in Tokyo.

The nuclear-armed North has worked to develop ballistic missiles that can perform “pull-up” maneuvers, allowing them to fly on irregular paths rather than typical ballistic trajectories. The development has complicated Japanese efforts to intercept and even track these weapons.

Japan operates a nationwide automatic warning and control system to defend against ballistic missile threats. But while radar can immediately calculate the parabolic flight paths of conventional ballistic missiles based on launch angle and speed, the new missiles are equipped with new capabilities.

Some analysts say they may be able to evade detection by sharply deviating from projected flight paths or by flying at low altitudes that — due to the curvature of the Earth — render some parts of the Korean Peninsula invisible to Japan-based radar systems.