United States has for the first time successfully tested its defence system against an intercontinental ballistic missile (ICBM). <br/><br/>The Missile Defense Agency said that a ground-based interceptor was launched at a California air base and shot down a mock ballistic missile. <br/><br/>The Pentagon said the test was long-planned but it comes amid increased tensions with North Korea. The test comes after Pyongyang fired its ninth missile this year. <br/><br/>Yesterday MDA Director Vice Adm Jim Syring called the test a critical milestone. It was the first live-fire test against a simulated ICBM for the Ground-Based Missile Defense.