North Korea announced Wednesday that its scientists had created a nuclear fusion reaction - a claim nuclear experts quickly cast doubt on.

"Nobody in the world has been able to sustain a controlled nuclear fusion reaction, the ultimate goal of nuclear technology," said Dan Pinkston, head of the Seoul office of the International Crisis Group. "I don't think the North Koreans are going to start ... putting nuclear power vendors around the world out of business any time soon."

Nuclear fusion is the same process that fuels stars, but has never been sustained in the laboratory by any nation, much less one of the poorest nations on earth. If scientists could harness fusion energy, it could become a long-term, inexpensive power source.

The state-run Korean Central News Agency reported the claim that was made in Rodong Shinmun - the North Korean Workers Party newspaper. The paper called it "artificial solar technology," adding the breakthrough represented "the development of new energy desired by humankind."

If North Korea has managed to advance nuclear fusion, it would be shocking development.

In March, an article in Scientific American magazine called "Fusion's False Dawn" said, "Scientists are now uncovering serious engineering challenges that could forestall the construction of such a plant for years to come."

The KCNA reported the process had been achieved on April 15 - "The Day of the Sun" - the birthday of Kim Il Sung, the late founder and "eternal president" of North Korea.

"Given that this is coming from the Rodong Shinmun, it is designed to strengthen the regime," said Dr. Kim Byung-ki, a security expert at Korea University. "The technological aspects have to be taken with a pinch of salt."