US military detects 'unprecedented levels' of North Korean submarine activity and evidence of nuclear 'ejection test'

The developments come amid heightened tensions between the United States and North Korea

The United States military has detected “highly unusual and unprecedented levels” of submarine activity by North Korea, including evidence of an “ejection test.”

Those detections come in the days following North Korea’s second intercontinental ballistic missile launch last month, defence officials told CNN.

An ejection test refers to a procedure that examines a submarine’s so-called “cold-launch” systems that allow a missile to be shot out of the vessel using pressurised air. Once launched into the air, the missile’s engines would then ignite as to avoid damaging the submarine with heat and flames.

The ejection test was the third in July, and the fourth for the year overall. Those launch capabilities are seen as critical to North Korea developing submarine launch capabilities.

The successful intercontinental ballistic missile test over the weekend reinforces the belief that Pyongyang wants to develop their nuclear and missile capabilities in order to establish legitimacy on the international front, and to deter other countries from attacking them.

The tests have exacerbated relations with Pyongyang and the United States, where Donald Trump has expressed concern about North Korea’s nuclear capabilities in the past. It is unclear how Mr Trump might respond to the latest developments, if he responds publicly at all.

Still, though, US defense officials aren’t convinced that North Korea has ambitions to actually attack the United States with a nuclear weapon. That’s at least in part because an attack on the US or on its western allies would be seen as a suicide mission for Pyongyang — western nations have a robust nuclear arsenal that would very likely be deployed in response to any such aggression.

North Korea’s testing has resulted in anxiety in the region, with both South Korea and Japan signaling that they are on high alert following the tests. Mr Trump has reportedly spoken with Japanese Prime Minister Shinzo Abe about the need to do more with regard to North Korea.

The US has acknowledged military-to-military conversations with those countries on the subject.