This marks the first time Mr Kim has directly commented on President Biden’s administration.
North Korea had earlier snubbed efforts by the new US government to establish diplomatic communication.
Mr Kim was speaking at a meeting of senior leaders in Pyongyang.
The ruling Workers’ Party central committee meeting started this week in the capital Pyongyang.
Mr Kim said they needed “especially to get fully prepared for confrontation in order to protect the dignity of our state and its interests for independent development”, as well as to guarantee a peaceful environment and North Korea’s security, according to state media outlet KCNA.
His latest comments come days after Mr Kim formally acknowledged that North Korea was facing concerns over food shortages.
Mr Kim’s relationship with Mr Biden’s administration has so far been fraught with tension.
