A target ballistic missile was downed near Hawaii late on Wednesday by the latest Raytheon Co-built Standard Missile-3 interceptor, the Pentagon's Missile Defense Agency (MDA) said.

The advanced interceptor is key to the next phase of an anti-missile shield being built by the United States in and around Europe.

The United States plans to deploy increasingly capable SM-3 versions up to around 2020 to boost defenses against missiles that could be fired by Iran and North Korea.

"Initial indications are that all components performed as designed," the agency said in an emailed statement.

The interceptor, called the SM-3 Block 1B, had failed to knock out its target in its maiden intercept test in September. This led to a continuing delay in Raytheon's production.

The shield under construction in Europe involves ground- and ship-based hardware as well as space-based sensors.

The SM-3 IB interceptor is due to be deployed on land in Romania by 2015 in the second stage of President Barack Obama's "phased adaptive" approach to missile defense. It will also be used on ships equipped with Lockheed Martin Corp's "Aegis" anti-missile combat system.

The Aegis system, named after the mythological shield that defended Zeus, ties together sensors, computers, displays, weapons launchers and weapons.

A total of 27 specially equipped Aegis warships are set up for ballistic missile defense - 23 in the U.S. Navy and four in the Japanese Maritime Self-Defense Force, according to Lockheed Martin, the Pentagon's No. 1 contractor by sales.

In the drill on Wednesday, a short-range ballistic target missile was launched from the Pacific Missile Range Facility, located on Kauai, Hawaii, MDA said.

The interceptor came from the USS Lake Erie, an Aegis cruiser that tracked the target and sent flight-path information to the SM-3 Block IB in-flight.

This set up a collision with a warhead, released by the SM-3, that destroyed the target by the force of impact known as "hit to kill," the MDA statement said.

Richard Lehner, an MDA spokesman, declined to say whether the test included countermeasures such as decoys that an enemy likely would use to try to overwhelm the defense.

"We don't divulge presence of countermeasures for any missile defense tests," he said in an email.

Critics such as Tom Collina, research director at the private Arms Control Association, maintain that intercept tests cannot show whether a system would work in the real world unless countermeasures are included.

Compared with the current SM-3 model, the new version features an improved target seeker, an advanced signal processor and better controls for adjusting its course.

Two more tests of the new version are scheduled to take place this year. Missile production decisions "will be made based upon system performance in any or all of the tests," Lehner said.

Riki Ellison, a prominent missile-defense advocate with close ties to military forces involved in the project, said the test on Wednesday could be viewed as a scenario involving North and South Korea. In this case, it could be a U.S. Aegis ship from the 7th fleet deployed in the Sea of Japan that would defend the South and the U.S. troops located there.

The latest test marked the 22nd successful intercept in 27 flight test attempts for the Aegis program, MDA said. It was the 53rd successful hit-to-kill intercept in 67 flight test attempts since the integrated system began development in 2001, according to MDA.

The latter number includes tests of components known as the Ground-based Midcourse Defense, Terminal High Altitude Area Defense and PATRIOT Advanced Capability-3 as well as the Aegis drills.

(Reporting By Jim Wolf; Editing by Andrew Heavens)

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