In an unusual step, North Korea has sent an open letter addressed to parliaments in several countries, declaring itself a "full-fledged nuclear power" and accusing President Donald Trump of "trying to drive the world into a horrible nuclear disaster," CNN reported.

Australian Foreign Minister Julie Bishop called the letter, dated Sept. 28, “unprecedented” and posted a copy of the cover letter on her verified Facebook page.

Her office confirmed to CNN that the letter, which was published by The Sydney Morning Herald, was genuine.

The letter appears to have been distributed a week after Trump’s address to the United Nations Security Council, after the president said that if the United States was forced to defend itself or its allies, it would have no choice “but to totally destroy North Korea.”

In the letter, North Korea condemned Trump’s statement and reiterated that it was tantamount to a declaration of war, CNN reported.

In the letter, North Korea condemned that statement as tantamount to a declaration of war, something North Korean officials said shortly after the speech. The United States denied that Trump had declared war on North Korea, which is also known as the Democratic People's Republic of Korea.

“If Trump thinks that he would bring the DPRK (Democratic People's Republic of Korea), a nuclear power, to its knees through nuclear war threat, it will be a big miscalculation and an expression of ignorance,” the letter said, according to CNN.

"I see (the letter) it as evidence that the collective strategy of imposing maximum diplomatic and economic pressure through sanctions on North Korea is working," Bishop said.