North Korean leader Kim Jong Un's sister has criticised the United States and South Korea for holding military exercises.
Kim Yo Jong issued a statement on Tuesday in which she warned Washington against further provocations if it wants a "good night's sleep for the next four years".
The comments are the first to be made by North Korea towards US President Joe Biden's administration.
It came as US Secretary of State Antony Blinken and Defence Secretary Lloyd Austin arrived in Asia to talk to allies Japan and South Korea about North Korea and other regional issues.
Pyongyang would consider abandoning a 2018 bilateral agreement on reducing military tensions and abolish a decades-old ruling party unit tasked to handle inter-Korean relations if it no longer had to cooperate with Seoul, said Kim Yo Jong, who handles inter-Korean affairs for the North.
She said Pyongyang would also consider scrapping an office that handled South Korean tours to the North's scenic Diamond Mountain, which Seoul suspended in 2008 after a North Korean guard shot and killed a South Korean tourist.
"We will keep an eye on [South Korea's] attitude and behaviour, and if they become more provocative, we could take exceptional measures," she said in her statement published in Pyongyang's official Rodong Sinmun newspaper.
"I would also like to take this opportunity to issue a word of advice to the new US administration, which is so eager to give off a smell of gunpowder in our land from across the ocean," she said.
"If they want to have a good night's sleep for the next four years, it would be good for them not to do things that would prevent them from sleeping properly from the start."
Challenges posed by North Korea's nuclear arsenal and China's growing influence loom large in the Biden administration's first Cabinet-level trip abroad, part of a larger effort to bolster US influence and calm concerns about Washington's role in Asia following four years of Donald Trump's "America First" approach.
The South Korean and US militaries began annual military exercises last week that continue through until Thursday.
The drills are command post exercises and computerised simulation and do not involve field training.
Ms Kim said even the smaller drills are an act of hostility toward the North.
In the past, Pyongyang has often responded to US-South Korea drills with missile tests.
"War rehearsals cannot co-exist with dialogue, hostility cannot co-exist with cooperation," she said.
A spokesperson from South Korea's defence ministry said the combined drills were defensive in nature and called for the North to show a more "flexible attitude" that would be constructive to stabilising peace on the Korean Peninsula.
He added that the South's military was not detecting any unusual signs of military activity from the North.
Cover image: North Korean leader Kim Jong Un pictured in 2019 during a missile launch (Picture: KCNA).