North Korea has warned that more sanctions and pressure will only make it accelerate its nuclear programme.
In a strongly worded statement, the foreign ministry called a new round of restrictions imposed by the United Nations “the most vicious, unethical and inhumane act of hostility”.
Meanwhile, the US and South Korea carried out joint military exercises over the Korean peninsula.
North Korea will be a key issue at the UN General Assembly this week.
The country fired its latest missile over Japan on Friday, in what was described as its farthest-reaching test.
The launch, which followed a fresh round of UN sanctions, was unanimously condemned by the UN Security Council as “highly provocative”.