Kim Jong Un's sister has warned the US to scrap future military exercises with South Korea if "it wants a good night's sleep for the next four years".
Kim Yo Jong issued a statement on Tuesday marking North Korea's first comments towards Joe Biden's administration
It comes 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 it 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 fatally shot 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."
The South Korean and US militaries began annual military exercises last week that will continue until Thursday.
The drills are command post exercises and computerised simulation and do not involve field training.
But 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 coexist with dialogue, hostility cannot coexist with cooperation," she said.
