ASIA North Korea works on nuclear missile plans, U.S. says

WASHINGTON (AP) -- 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.
Having agreed to a self-imposed test ban, North Korea is sharing technology information with Iran, which carries out missile tests on North Korea's behalf, the administration official said, speaking on condition of anonymity.
The missile program is based on Russian technology and has been conducted with help from Russian scientists -- help 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 new ballistic missile systems that "appreciably expand the ballistic-missile threat."A version of the missile capable of being launched from a submarine or a ship is potentially the most threatening, the weekly said.
Important questions
One important question, he said, is whether the missiles are exactly patterned on a Russian model. Another, he said, is whether the missiles could reach the United States.
U.S. officials think North Korea may have the technology for a submarine-launched ballistic missile, but it is not clear whether North Korea has a missile platform, the official said.
The Bush administration is working with South Korea, Japan, China and Russia to negotiate an agreement with North Korea to end its nuclear weapons program.