The U.S. may be in range of North Korean weapons, South Korea announced Sunday.
After retrieving and analyzing part of the rocket its neighbour launched on December 12, South Korea believes the North has the technology to reach the United States west coast.
A South Korean Defence Ministry official said that the rocket could carry a 500-600 kilogramme warhead more than 10,000 kilometers.
The recovered oxidizer tank of the rocket contained red fuming nitric acid, a chemical used in Soviet missiles.
But experts believe the North is still years away from mastering the technology needed to miniaturise a nuclear bomb to mount on a missile.
After earlier failed launches, the rocket test this month was a boost at home for the credibility of North Korean leader Kim Jong-un, who came to power when his father died last year.
