North Korea threatens pre-emptive strike against South

North Korea has said its military is ready to pre-emptively attack and "liberate" Seoul, in its latest outburst against the joint military drills by the United States and South Korea.

In a statement carried through state media, the North's Korean People's Army said its front-line units were prepared to strike first if they saw signs that American and South Korean troops involved in the annual drills were attempting to invade the North.