North Korea has defended its weapons programme, saying it needs the capability to launch intercontinental missiles at the heart of the United States to prevent an invasion.
It warned that the country was ready to give the US a "severe lesson" with its strategic nuclear force if it takes military action against it, it said in a statement to a regional meeting in Manila.
In a transcript of a statement by the North's foreign minister, RiYong-ho, Pyongyang called new UN sanctions "fabricated" and warned there would be "strong follow-up measures" and acts of justice.
"We will under no circumstances put the nukes and ballistic rockets on the negotiating table," Mr Ri said.
The statement said the North's intercontinental ballistic missile tests in July proved that the entire United States was in its firing range, and those missiles were a legitimate means of self-defence.
Mr Ri also said that his country has no intention of using nuclear weapons against any country "except the US", unless another country joined in an American action against North Korea.