North Korea missile test
© KCNA / Reuters
Pyongyang says the missiles it fired toward Japan were part of an exercise targeting US military bases there. It comes as the White House announced the deployment of the advanced THAAD anti-missile defense system to South Korea to guard against the North.

The test launches of four missiles, fired by North Korea into the Sea of Japan on Monday morning, were a drill carried out by an army unit commissioned with attacking US military bases in Japan, the country's official news agency KCNA said Tuesday.

North Korean leader Kim Jong-un personally supervised the drill, it said.

The launch was preceded by threats of retaliation to the US-South Korea military drills. Pyongyang views the exercises as a preparation of an attack on North Korea.

Meanwhile, the White House said Monday that a THAAD missile defense system will be stationed in South Korea to counter threats from the North.

White House press secretary Sean Spicer described the Monday morning launches as consistent with Pyongyang's history of "provocative behavior."

"The Trump administration is taking steps to enhance our ability to defend against North Korea's ballistic missiles, such as through the deployment of a THAAD battery to South Korea," Spicer told reporters at a press briefing Monday.

The THAAD, or Terminal High Altitude Area Defense, is a missile defense system designed to intercept short-and-medium-range ballistic missiles as they begin their descent to their targets.

Developed by Lockheed Martin, THAAD missiles use infrared seeker technology to locate their targets and detonate on impact. The US has been planning to set up THAAD in South Korea since July 2016, adding to its already existing defensive capabilities in the Asia-Pacific region.
Terminal High Altitude Area Defense (THAAD)
© U.S. Department of Defense / Reuters A Terminal High Altitude Area Defense (THAAD).