North Korean Dictator Kim Jong Un was grinning when he visited the shipyards where a new threat is under construction: a “strategic guided-missile submarine” that’s able to strike the United States with ten nuclear missiles. The North Korean leader vowed to expand the country’s weaponry in 2021 to confront supposed U.S. military threats. He has also sought intercontinental ballistic missiles, hypersonic weapons, multi-warhead missiles, and spy satellites. Some experts suspect that North Korea could have received Russian assistance to build nukes in return for sending soldiers to help with the war against Ukraine. Submarine attacks pose a heightened risk because they’re harder to detect than other conventional weapons. Jong Un said that the submarine was a critical first step in building a nuclear-armed navy to oppose the U.S. and its allies in Asia. North Korea will likely test the submarine’s capability in the next two years before deploying it.