North Korea tests missiles and warns of "thermonuclear war" as US and South Korea start military drills

North Korean leader Kim Jong Un oversaw cruise missile tests from a navy ship.
The US and South Korea began their annual joint military exercises that North Korea views as rehearsal for invasion.
North Korea warned of potential "thermonuclear war" in response to the drills and recent trilateral agreements.
The US, South Korea, and Japan agreed to enhance cooperation on missile defense systems against North Korea.
North Korea plans to launch a satellite later this month, raising international concerns over its missile capabilities.