North Korea threatens US, South Korea with 'merciless retaliation' over drills

North Korea has again aimed fiery rhetoric at the U.S. and South Korea, this time threatening "merciless retaliation" over ongoing joint military drills.

According to quotes published in North Korea's state-run KCNA outlet, the hermit regime says both the United States and South Korea should "take the whole responsibility for catastrophic results from (a) reckless war game." The drills began on Monday and will involve some 17,500 U.S. troops and 50,000 South Korean forces.

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While North Korea views the annual drills as preparation for invasion, the U.S. has described them as critical to maintaining readiness.

"A strong diplomatic effort backed by a strong military effort is key because credible combat power should be in support of diplomacy and not the other way around," commander of U.S. forces in the Pacific, Adm. Harry Harris, said during a news conference in South Korea.

The doomsday language out of Kim Jong Un's regime comes as a Pyongyang envoy said on Tuesday that North Korea's self-defensive nuclear deterrence arsenal will "never" be on the negotiating table.