Pyongyang Demonstrates Heavy Levels Of Sub Activity; U.S. Also Notes Missile Ejection Trial

The United States has detected what are seen to be "highly unusual and unprecedented levels" of North Korean submarine activity and signs of an "ejection test" following Pyongyang's intercontinental ballistic missile test on July 28, a U.S. defense official tells CNN.

An ejection test involves a missile's cold-launch system, which uses high-pressure steam to propel a missile out of its launch canister into the air before its engines ignite.

This helps prevent flames and heat...