U.S. Says N. Korea Developing Missiles

WASHINGTON â€”  The United States has determined that North Korea is working on new ballistic missile systems designed to deliver nuclear warheads and that it is testing the technology by proxy in Iran, a Bush administration official said Thursday.

North Korea, which has agreed to a self-imposed test ban, is sharing technology information with Iran, which carries out missile tests on its behalf, the administration official said, speaking on condition of anonymity.

The missile program is based on technology developed by Russia and has been conducted with the help of Russian scientists -- help that the United States thinks may be continuing, the official said.

A leading military publication, Jane’s Defense Weekly, reported recently that North Korea was developing two systems that “appreciably expand the ballistic missile threat.�

A version of the missile that could be launched from a submarine or a ship is potentially the most threatening, the publication said.

Not all of the details of the North Korean program are known to the United States, the administration official said.

One important question, he said, is whether the missiles are patterned exactly on a Russian model.

Another, he said, is whether the missiles could reach the United States.

U.S. officials believe that North Korea may have the technology for a submarine-launched ballistic missile, but it is not clear whether the country has a missile platform, the administration official said.

The administration is working with South Korea, Japan, China and Russia to negotiate an agreement with North Korea to end its nuclear weapons program.