North Korea has placed its military on alert and warned of "disastrous consequences" in response to a United States-led military drill near the Korean peninsula.
A North Korean military spokesman Tuesday told state media all troops have been ordered to "keep themselves ready to promptly launch operations at any time."
South Korean Defense Ministry spokesman Kim Min-seok confirmed North Korea's military has been placed on high alert.
The threat comes as the U.S. moved a group of ships to the South Korean port of Busan for what officials describe as a routine search and rescue drill.
Pyongyang seems to be particularly upset about the participation of the USS George Washington, a nuclear-powered aircraft carrier.
The article in the Korean Central News Agency (KCNA) claimed the ship was carrying "at least 100 nuclear bombs aboard."
It warned the closer that U.S. forces get to North Korea, "the more unpredictable disasters their actions will cause."
Pyongyang often threatens military action in response to the U.S.-South Korean drills, but rarely follows through.