SEOUL, South Korea — North Korea on Sunday accused Secretary of State Hillary Rodham Clinton of being “reckless” for advising its new leader to give priority to improving the lives of his people instead of spending money on weapons.

North Korea can now “steadily boost its nuclear deterrent by itself without letting its people fasten their belts any longer,” the North’s official Korean Central News Agency quoted a North Korean Foreign Ministry spokesman as saying.

The United States and South Korea often claim that North Korea is impoverishing its people by diverting its scant resources into building nuclear weapons and long-range missiles.

On Thursday, Mrs. Clinton urged the new leader, Kim Jong-un, to chart a course different from that of his father, Kim Jong-il, whose sudden death in December left his relatively inexperienced third son at the helm. The son, still believed to be in his late 20s, has vowed to continue his father’s “military first” policy.