The North Korean army said it has final approval to launch "merciless" military strikes against the United States, including the use of nuclear weapons.
In a statement published by the North's official KCNA news agency, the General Staff of the Korean People's Army said the United States had been formally informed that its "reckless nuclear threat" would be "smashed by strong will of all the united service personnel... and cutting-edge smaller, lighter and diversified nuclear strike means," according to Reuters.
"The moment of explosion is approaching fast," the statement reads, warning that war could break out "today or tomorrow."
"The merciless operation of our revolutionary armed forces in this regard has been finally examined and ratified," it read.
According to South Korean news agency Yonhap, the statement also said the North would "take a series of strong, actual military countermeasures as the Supreme Command solemnly declared at home and abroad."
US Defense Secretary Chuck Hagel said on Wednesday that the hermit kingdom's threats presented a "real and clear danger" to the United States and its allies, South Korea and Japan.