- But ultimately no progress was made towards Washington's declared aim of denuclearising North Korea, which is under multiple international sanctions for its banned weapons programmes.
SEOUL: North Korean leader Kim Jong Un's influential sister warned the United States against actions that could make it "lose sleep", state media reported Tuesday, as top Biden administration officials began a visit to key allies Tokyo and Seoul.
Pentagon chief Lloyd Austin and Secretary of State Antony Blinken arrived in Japan on Monday on their first overseas trip, aimed at rallying military alliances as a bulwark against China and cementing a united front against the nuclear-armed North.
The statement by Kim Yo Jong, a key adviser to her brother, was Pyongyang's first explicit reference to the new president in Washington, more than four months after Joe Biden was elected to replace Donald Trump -- although it still did not mention the Democrat by name.
The United States and South Korea began joint military exercises last week and Pyongyang's official Rodong Sinmun newspaper carried a statement from her offering "a word of advice to the new administration of the United States that is struggling to spread the smell of gunpowder on our land".
"If you wish to sleep well for the next four years, it would be better not to create work from the start that will make you lose sleep," she said.
Trump's unorthodox approach to foreign policy saw him trade insults and threats of war with Kim Jong Un before an extraordinary diplomatic bromance that saw a series of headline-grabbing meetings.
But ultimately no progress was made towards Washington's declared aim of denuclearising North Korea, which is under multiple international sanctions for its banned weapons programmes.
It has isolated itself further, imposing a strict border closure to protect itself against the coronavirus pandemic that first emerged in neighbouring China.
Shortly before Biden's January inauguration, leader Kim decried the US as his country's "foremost principal enemy" and Pyongyang unveiled a new submarine-launched ballistic missile at a military parade.