The US have warned North Korea that any use of nuclear weapons “will result in the end of that regime”.
The unambiguous warning comes as the rogue state launched two short-range ballistic missiles towards the Sea of Japan, the latest step in escalating tensions in the region.
On Monday forces of South and North Korea exchanged warning shots off the west coast of the peninsula.
Governments from both nations accused each other of breaching their maritime borders, in a sign the South may be taking a stricter line towards its rogue neighbour to the north.
Regarding this latest missile launch, South Korea’s Yonhap News Agency reported on Friday: “The Joint Chiefs of Staff (JCS) said it detected the launches from the Tongchon area in Kangwon Province."
The warning to North Korea came within the US' 2022 National Defense Strategy.
The Department of Defense report includes assessments from various countries' nuclear capabilities in the Nuclear Posture Review.
In it US officials emphasised the need to "to make clear to the Kim regime the dire consequences should it use nuclear weapons".
It went on: "Any nuclear attack by North Korea against the United States or its Allies and partners is unacceptable and will result in the end of that regime.
"There is no scenario in which the Kim regime could employ nuclear weapons and survive."
It also affirmed the value of the US' own nuclear arsenal for deterring any North Korean attacks in East Asia.
The Japanese Ministry of Defence confirmed two ballistic weapons had been fired, but that none had landed within their territory.
They added that they would continue to "collect and analyse" information on the exact type of weapon used.
Kim Jong-un's latest launch came as South Korea's National Defence Training, an annual series of military exercises, entered its tenth day.
The drills had drawn huge condemnation in North Korean state media, with one propaganda outlet warning: "Through the provocative nature, content, and unprecedented scale of this exercise, it is clear to what extent the belligerent courage of the puppet military belligerents is reaching.
"You will face even greater criticism and condemnation."
Regarding the exchange of fire, a statement on Monday from the South's Joint Chiefs of Staff (JCS) said warnings had been broadcast and warning shots fired after a merchant vessel crossed the Northern Limit Line (NLL) at about 3.40am local time (6.40pm UK time).
North Korea, meanwhile, said via state media that it had fired 10 rocket artillery rounds after a South Korean navy ship had violated the NLL and fired warning shots "on the pretext of tracking down an unidentified ship".
The official KCNA news agency reported a spokesperson for the General Staff of the North's Korean People's Army as saying: "We ordered initial countermeasures to strongly expel the enemy warship."
But the South's JCS said it had conducted a "normal operation", describing the North's move as a violation of a bilateral military pact in 2018 which had banned "hostile acts" in the border areas.