South Korea says any future nuclear test by North Korea risks collapsing its mountain test site and triggering a radiation leak.

South Korea's weather agency chief Nam Jae-Cheol made the comments Monday during a parliament committee meeting. He was responding to a lawmaker's question about whether another North Korean test could lead to such an accident.

South Korea detected several earthquakes near the North's nuclear test site in the country's northeast after its sixth and most powerful bomb explosion in September. Experts say the quakes suggest the area is now too unstable to conduct more tests there.