WASHINGTON (Reuters) - The U.S. military conducted a successful test of its system built to knock out long-range missiles that could be fired by North Korea or Iran, the Pentagon said on Friday.

The target missile for the test over the Pacific was launched from Kodiak, Alaska and an interceptor was launched from Vandenberg Air Force Base, California, officials said. The intercept took place at 3:29 p.m. EST .

Boeing Co is prime contractor for the system, called the ground-based midcourse defense.

The Pentagon will hold a briefing on the results of the test at 5:15 p.m. EST (0015 GMT), officials said.

U.S. officials had billed the test as a particularly realistic simulation of a possible missile attack but critics of the system disputed that description.

Before the latest test, the Pentagon said 12 tests of the ground-based system had been conducted since 1999 and seven of them had been successful.

Advisers to U.S. President-elect Barack Obama have said he favors missile defense in principle but the program, a flagship policy of the Bush administration, will face more scrutiny after he takes office.

President George W. Bush has been spending roughly $10 billion a year on all aspects of missile defense, the Pentagon’s costliest annual outlay for an arms development program.

The United States and Russia are at odds over a Bush administration plan to extend the Boeing-managed system into Eastern Europe, using 10 silo-based two-stage interceptors in Poland and a related radar system in the Czech Republic.