North Korea's former second in command has blasted President Roh Moo-hyun's "balancing role" idea for South Korea, saying it should be sought only after reunification.

Hwang Jang-yup, a former secretary of the North's Workers' Party who defected to the South in 1996, made the remarks Friday in a forum hosted by the main opposition Grand National Party.

He said it is nonsense for the government to seek a mediating role while neglecting its alliance with the United States.

On the North's nuclear program, Hwang said Pyongyang has probably reprocessed half of the eight thousand spent fuel rods to secure enough weapons-grade plutonium to make several bombs within months.

In 2003, the North said it finished reprocessing about eight thousand spent fuel rods and extracted plutonium from them to strengthen its "nuclear deterrence."