--- description: North Korea has been engaged in "highly unusual and unprecedented levels" of submarine activity, according to the U.S. military title: North Korea: U.S. Detects Highly Unusual Submarine Activity image: https://static.time.com/v3/assets/bltea6093859af6183b/bltbebcd45e57535cde/6988d7eb096a94c81e69ef8d/gettyimages-595014782.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 ---  * [World](/section/world/) ## World Update your preferences in [Account Settings](/account/preferences/) Close * [North Korea](/tag/north-korea/) ## North Korea Update your preferences in [Account Settings](/account/preferences/) Close # The U.S. Military Has Detected 'Highly Unusual' North Korean Submarine Activity by [Joseph Hincks](/author/joseph-hincks/) ## Joseph Hincks Update your preferences in [Account Settings](/account/preferences/) Close Aug 1, 2017 4:59 AM CUT  This undated picture released from North Korea's official Korean Central News Agency on Aug.t 25, 2016 shows Kim Jong-Un inspecting a test-fire of submarine-launched ballistic missile at an undisclosed location. This undated picture released from North Korea's official Korean Central News Agency on Aug.t 25, 2016 shows Kim Jong-Un inspecting a test-fire of submarine-launched ballistic missile at an undisclosed location.KNS—AFP/Getty Images by [Joseph Hincks](/author/joseph-hincks/) ## Joseph Hincks Update your preferences in [Account Settings](/account/preferences/) Close Aug 1, 2017 4:59 AM CUT North Korea has been engaged in “highly unusual and unprecedented levels” of[ submarine activity](http://edition.cnn.com/2017/07/31/politics/north-korea-ejection-test-submarine-activity/index.html "undefined") in the wake of its second intercontinental ballistic missile launch this month, according to analysis by the U.S. military. Speaking with CNN, an unnamed U.S. defense official said Monday the military also detected evidence of an “ejection test” Sunday at the Sinpo Naval Shipyard on the country’s eastern seaboard. Sinpo functions as a center of North Korea’s submarine-launched ballistic missile program. Ejection tests like Sunday’s — of which CNN says there have been four this year, three in July alone — test the efficacy of a launch component critical to developing submarine missile launch capability. According to U.S. intelligence assessments, Pyongyang’s submarine fleet comprises about 70 subs, but few are thought to be new or sophisticated enough to fire missiles and the submarine-based launch program is still in its nascent stages. Earlier in July CNN [reported](http://edition.cnn.com/2017/07/19/politics/north-korea-possible-missile-test/index.html "undefined") that one of the older class of North Korean subs, a Romeo, had sailed some 62 miles out to sea in international waters. The U.S. and South Korea slightly raised their alert level in response to its unusual deployment and range. **Read More:** [_North Korea: There Is No Good Option_](http://time.com/4856217/no-good-options-on-north-korea/ "undefined") Pyongyang fired either a KN-11 or a Pukguksong-1 missile from a submarine last summer, in what officials believe was the country’s first successful submarine missile test. North Korean leader Kim Jong Un [claimed](http://time.com/4879527/kim-jong-un-north-korea-missile-could-strike-entire-continental-u-s/ "undefined") last week that “the entire U.S. territory is within our shooting range” after its latest missile launch, further [ratcheting up tensions](http://time.com/4879902/north-korea-thaad-icbm-missiles-test-launch/ "undefined") with Washington. \[[CNN](http://edition.cnn.com/2017/07/31/politics/north-korea-ejection-test-submarine-activity/index.html "undefined")\] ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/4881840/north-korea-submarine-missile/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/4881840/north-korea-submarine-missile/"},"headline":"The U.S. Military Has Detected 'Highly Unusual' North Korean Submarine Activity","datePublished":"2017-08-01T04:59:39.000Z","dateModified":"2026-02-23T16:48:47.380Z","description":"The military also detected evidence of an \"ejection test\"","url":"https://time.com/4881840/north-korea-submarine-missile/","keywords":["North Korea","onetime"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/bltbebcd45e57535cde/6988d7eb096a94c81e69ef8d/gettyimages-595014782.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Joseph Hincks","jobTitle":null,"url":"https://time.com/author/joseph-hincks/"}],"articleSection":"World","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/bltbebcd45e57535cde/6988d7eb096a94c81e69ef8d/gettyimages-595014782.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"NKOREA-POLITICS-KIM","caption":"NKOREA-POLITICS-KIM","creditText":"KNS—AFP/Getty Images","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/world/","name":"World"}},{"@type":"ListItem","position":2,"item":{"@id":"/tag/north-korea/","name":"North Korea"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/4881840/north-korea-submarine-missile/","name":"The U.S. Military Has Detected 'Highly Unusual' North Korean Submarine Activity"}}]}] ```