North Korea says it has fired two short-range ballistic missiles to simulate nuclear strikes on military targets in South Korea.
State media said the tests were held as a warning against the US deployment of strategic bombers to the region.
South Korean media reported the missiles were fired off the east coast around midnight.
The launches come amid Washington and Seoul's annual military drills- which always provoke the North.
Pyongyang has long denounced the combined drills as the US' rehearsal for war.
North Korea's army said the missiles had been fired late on Wednesday in a "tactical nuclear strike drill simulating scorched earth strikes at major command centres and operational airfields" in South Korea.
"The drill is aimed to send a clear message to the enemies" who "challenge us with such military threats as the deployment of strategic nuclear assets despite our repeated warnings," the army said.
South Korea's unification ministry strongly condemned Pyongyang for openly revealing its intent to attack the South.
"The more the North is obsessed with military threats and provocations, the more it will face overwhelming responses by South Korea, the US and Japan," a ministry official said.
Japan's Prime Minister Fumio Kishida also criticised the launches, which he said not only threatened the peace and stability of Japan, but also the international community.
North Korea has conducted a record number of weapons tests this year. The latest come a day before South Korea and the US end 11 days of Ulchi Freedom Shield military drills.
The defence exercises involved at least one US B-1B strategic bomber flying above the Korean Peninsula, according to South Korean media.
North Korean leader Kim Jong Un observed a drill on Tuesday preparing his top commanders for all-out war with the South, according to state media.
The drill simulated repelling a sudden invasion, then launching a counter-attack to occupy "the whole territory of the southern half", the report said.
Despite UN sanctions, Kim Jong Un has repeatedly vowed to increase his country's production of nuclear warheads and development of more powerful weapons.
Pyongyang this year has continued regular tests of its missiles after launching a record number in 2022 – including ones capable of reaching US territory.
In recent months, it has also attempted, unsuccessfully, to launch two space satellites.
Meanwhile, the US said on Wednesday that Pyongyang was in "active" negotiations with Russia on a potential arms deal.
Last month, Russia's defence minister visited Pyongyang where he was given a very public tour of North Korea's weapons.
The US says Mr Shoigu used the trip to try to convince North Korea to sell him weapons and ammunition.
"Following these negotiations, high level discussions may continue in coming months," the spokesman of the US National Security Council John Kirby told reporters on Wednesday.
"Now, among these potential deals, Russia would receive significant quantities and multiple types of munitions from [North Korea], which the Russian military plans to use in Ukraine."
Pyongyang has repeatedly dismissed accusations that it has been shipping weapons to Russia in support of its invasion of Ukraine.
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