The submarine could significantly escalate security concerns on the Korean peninsula and in the Taiwan Strait, experts say North Korea's construction of a nuclear-powered submarine could significantly escalate security concerns on the peninsula and in the Taiwan Strait,

North Korea has conducted a slew of underwater-launched ballistic missile tests since 2016, but all launches were made from the same 2,000-tonne-class submarine which has a single launch tube. Many experts call it a test platform, rather than an operational submarine in active service.

South Korea relies on security guarantees from the US to deter North Korean aggression, providing sites that host about 28,500 American troops. Earlier in March, a nuclear-powered US aircraft carrier docked at a South Korean port, prompting the sister of North Korean leader Kim Jong Un to denounce the deployment of strategic assets in the region.

North Korea condemned an ongoing U.S.-South Korea joint military exercise Wednesday, saying another incident like Seoul's recent accidental bombing of its own village near the DMZ could lead to "a new armed conflict.

North Korea has issued a sharp rebuke over the major military exercise being carried out by the U.S. and its South Korean ally, labeling the training a "war rehearsal." Newsweek reached out to the Pentagon and the South Korean embassy in the U.

North Korea denounced joint military drills between the US and South Korea saying the South Korean Air Force’s recent bombing mistake shows the risk of the region unintentionally getting dragged into a new armed conflict.

North Korea fired several ballistic missiles into the sea on Monday in what was the latest display of the communist country’s military capabilities. The missile launches were reportedly in response to the joint military drills conducted in the region between the U.

North Korea on Wednesday continued to denounce joint military drills by South Korea and the United States, claiming South Korean jet fighters' latest accidental bombing of a village was an "ominous" sign that points to the danger of the exercise.