North Korean nuclear tests could serve as advertisement for weapon sales

The most immediate threat to the United States from North Korea could be the latter's willingness to sell nuclear material or knowledge to countries that sponsor terrorism, according to nuclear experts.

Last year, Japan seized cargo believed to be from North Korea containing material that could be used in the construction of nuclear centrifuges. The centrifuges are necessary for the enrichment of uranium into bomb fuel. North Korea has yet to show proof it can build a nuclear warhead small enough to mount on a missile, but Pyongyang may be able to help other countries develop nuclear expertise, Associated Press reports.

"There's a growing technical capability and confidence to sell weapons and technology abroad, without fear of reprisal, and that lack of fear comes from (their) growing nuclear capabilities," Joel Wit, a former U.S. State Department official, said, according to Associated Press.

North Korea unveiled a long-suspected uranium enrichment operation in late 2010. Pyongyang conducted nuclear tests in 2006 and 2009. On February 12, North Korea conducted a third underground test and may have used uranium as opposed to plutonium in the exercise.

"Testing a uranium-based bomb would announce to the world - including potential buyers - that North Korea is now operating a new, undiscovered production line for weapons-usable material," Graham Allison, the director of the Belfer Center for Science and International Affairs at the Harvard Kennedy School, said, according to the New York Times.

Sanctions against North Korea cut down on missile sales between countries, but Iran and Syria may continue to be Pyongyang's nuclear customers. North Korea may have helped Syria build a secret plutonium reactor, which Israeli jets bombed in 2007.

Secret nuclear trade is a major concern for experts, as it is not known how a buyer would use the atomic material and information or where it could be sold, Associated Press reports.

"The terrorist threat of an improvised nuclear device delivered anonymously and unconventionally by a boat or a truck across our long and unprotected borders is one against which we have no certain deterrent or defensive response," Robert Gallucci, a former senior U.S. diplomat, said, according to Associated Press. "For Americans, this threat is far greater than the unlikely threat that may someday be posed by North Korean nuclear weapons delivered by a ballistic missile."