This week, North Korea claimed to have pulled off another grand feat in its weapons development journey—a successful test of a hypersonic intermediate-range ballistic missile (IRBM).

The missile, according to North Korea’s state media, is designed to hit distant targets in the Pacific with lightning speed and precision. While Kim Jong Un hailed it as a significant boost to the nation’s nuclear deterrence, not everyone is buying the hype.

Here’s what we know so far.

What North Korea Claims

North Korea’s official Korean Central News Agency (KCNA) painted a dramatic picture of the test. The missile reportedly traveled 1,500 kilometers (932 miles), reached two separate peaks at 99.8 and 42.5 kilometers, and hit speeds 12 times the speed of sound before striking a simulated sea target.

North Korean leader Kim himself observed the launch remotely and declared it a crucial step toward building a nuclear arsenal that no rival could challenge. He emphasized that this wasn’t an offensive move but a necessary measure for self-defense, aiming to deter threats to North Korea’s security.

No specific countries were mentioned, but it’s clear the “rivals in the Pacific” he referred to likely include South Korea, Japan, and the United States.

South Korea and Japan Call Foul

South Korea and Japan, however, are calling North Korea’s bluff—or at least part of it.

According to South Korea’s Joint Chiefs of Staff (JCS), the missile didn’t perform as impressively as KCNA claimed, as reported by USNI News. Seoul’s analysis showed the missile flew a shorter distance of 1,100 kilometers (684 miles) and didn’t reach the supposed second peak.