North Korea is engaging in "highly unusual and unprecedented levels" of submarine activity following its intercontinental ballistic missile test on Friday, alarming the U.S. and South Korean militaries, CNN reports.
North Korea has around 70 submarines in its fleet, although most are old and unable to fire missiles. Additionally, intelligence suggests that the country's missile programs for its capable submarines are only in the early stages, Still, when considered with Pyongyang's second intercontinental ballistic missile test this month, the "developments are concerning because North Korea says it is trying to develop a missile capable of delivering a nuclear warhead to the United States," CNN writes.
In addition to increased submarine activity, a U.S. defense official told CNN that there is also evidence of a North Korean "ejection test," which would explore the steam system used to launch a missile out of a canister far enough as to not damage a submarine before the missile's engines ignited. The test was conducted on land, and is the fourth such test the nation has done this year.
Experts say Friday's intercontinental missile test, if conducted on flat land and with an altered trajectory, could have reached as far as Chicago. For more on how the U.S. ought to handle North Korea, check out this analysis from The Week's Harry J. Kazianis.