The US military says, it has begun deploying an anti-ballistic missile defense system to South Korea, following a string of missile tests by North Korea. The announcement came after North Korea launched four missiles yesterday which it said was part of training for a strike on US bases in Japan. <br/><br/>The Pacific Command, which oversees US military operations in the Asia-Pacific said in a statement that the deployment of the Terminal High Altitude Area Defense (THAAD) system contributes to a layered missile defense system and enhances the US-ROK Alliance's defense against North Korean missile threats. It said, the system is meant to intercept and destroy short and medium-range ballistic missiles during their final phase of flight.