The threat comes after the UN Security Council unanimously approved new sanctions against Pyongyang
North Korea has threatened to launch "thousands-fold" revenge against the US after tough UN sanctions were imposed on it following the test firing of intercontinental ballistic missiles.
In a statement on Monday, Pyongyang said the sanctions were caused by a "heinous US plot to isolate and stifle" North Korea.
"We will not put our self-defensive nuclear deterrent on the negotiating table," it said, "and will never take a single step back from strengthening our nuclear might."
The statement, carried by North Korea's official Korea Central News Agency, also threatened to make the US "pay the price for its crime... thousands of times."
It said the UN sanctions would not force the country to negotiate over its nuclear programme or give up its ambitions and warned it would take "action of justice," although it did not elaborate on what that means.
It comes two days after the UN Security Council unanimously approved new sanctions against Pyongyang, including a ban on coal and other exports worth more than £770m.
US Secretary of State Rex Tillerson has ruled out a quick return to dialogue with North Korea, saying the new sanctions showed the world had run out of patience with Pyongyang's nuclear ambitions.
He said: "The best signal that North Korea could send that they're prepared to talk would be to stop these missile launches."
Last month, North Korea carried out two intercontinental ballistic missile tests, with leader Kim Jong-Un boasting he could strike any part of the US.
A White House statement said US President Donald Trump and his South Korean counterpart Moon Jae-In spoke on the phone on Sunday and agreed Pyongyang "poses a grave and growing direct threat."
Just completed call with President Moon of South Korea. Very happy and impressed with 15-0 United Nations vote on North Korea sanctions.— Donald J. Trump (@realDonaldTrump) August 7, 2017
Mr Trump thanked Russia and China on Twitter for backing the new sanctions, adding he was "very happy and impressed with 15-0 United Nations vote on North Korea sanctions."