Report criticizes U.S. missile-defense system

A congressionally-requested report on the current U.S. missile-defense system says the best way to meet future threats from Iran or North Korea is to place upgraded missiles and improved radars on both coasts of the U.S.

The current U.S. system is "very expensive and has limited effectiveness," said the report from the National Research Council, which offers advice to government agencies under a congressional charter.

Fashioned amid tensions with North Korea over the last two decades, the U.S. Missile Defense Agency's system now has 30 interceptor missiles ready to launch from bases in Alaska and California, as well as smaller ship-based systems aboard the U.S. Navy's Pacific and Atlantic Fleet.

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