The Missile Defense Agency said the laser test shot down an incoming ballistic missile in its first stage of launch over the Pacific Ocean. The Feb. 12 test was said to mark the first time a laser destroyed a ballistic missile.

"This was the first directed energy lethal intercept demonstration against a liquid-fuel boosting ballistic missile target from an airborne platform," the Pentagon agency said.

Officials said the test marked a major achievement for the troubled Airborne Laser program, about five years behind schedule. In April 2009, Defense Secretary Robert Gates recommended canceling ABL and limiting the program to research and development.

ABL has comprised the development and installation of a high-powered chemical oxygen iodine laser aboard a Boeing 747-400F jet. Prime contractor Boeing has been responsible for integration while Northrop Grumman and Lockheed Martin provided the laser and fire control systems, respectively.

Over the last 18 months, ABL was revived with a series of successful tests. ABL was said to have a range of 300 kilometers, sufficient to intercept ballistic missiles in the first, or boost phase, of launch.

"The revolutionary use of directed energy is very attractive for missile defense, with the potential to attack multiple targets at the speed of light, at a range of hundreds of kilometers and at a low cost per intercept attempt compared to current technologies," MDA said.

The agency said a short-range ballistic missile was fired from a mobile launch sea platform. Seconds later, the Airborne Laser test bed detected the missile in its boost phase.

Officials said the 747 aircraft fired two low-energy lasers to track the target. The second beam was emitted to ensure the location of the missile to compensate for atmospheric changes.

"Finally, the ALTB fired its megawatt-class high energy laser, heating the boosting ballistic missile to critical structural failure," MDA said. "The entire engagement occurred within two minutes of the target missile launch, while its rocket motors were still thrusting."

Boeing said ALTB marked the most powerful mobile laser device in the world. Executives said the airborne laser would require additional research and development.

Over the last month, ABL scored an additional two successes. On Feb. 3, the system destroyed a solid-fuel missile during its boost phase. In January, the laser intercepted rather than destroyed a so-called Missile Alternative Range Target Instrument.

"ALTB technology and future directed-energy platforms will transform how the United States defends itself and its friends and allies," Boeing vice president Michael Rinn said.