“The whole world should clearly remember it was the US who first declared war on our country,” foreign minister Ri Yong-ho said from New York.
He added: “In light of the declaration of war by Trump, all options will be on the operations table of the supreme leadership of the [Democratic Peoples Republic of Korea].”
The White House called the Foreign Minister's comments "absurd".
"We've not declared war on North Korea. Frankly, the suggestion of that is absurd," White House spokeswoman Sarah Sanders said.
Mr Trump appeared to threaten regime change in the country over the weekend, tweeting that Mr Ri “won’t be around much longer” if he continued to echo the thoughts of North Korean leader Kim Jong-un.
Mr Ri told the UN General Assembly on Saturday that targeting the US mainland with its rockets was inevitable after “Mr Evil President” Trump called Kim a “rocket man” on a suicide mission in his own UN address.
Responding to that, Mr Trump tweeted: “Just heard foreign minister of North Korea speak at UN If he echoes thoughts of Little Rocket Man, they won’t be around much longer!”
Leaving the UN on Monday, Mr Ri said that following the latest tweet his country now had “every right to make countermeasures, including the right to shoot down United States strategic bombers even when they are not inside the airspace border of our country”.
The day before, the US flew fighter jets close to North Korea’s east coast – the farthest north any US fighter plane has flown over the demilitarised zone this century, according to the Pentagon. A Pentagon spokeswoman said the flyover was intended as a message to North Korea that Mr Trump had many military options at his disposal.
“We are prepared to use the full range of military capabilities to defend the US homeland and our allies,” said spokeswoman Dana White.
The Pentagon followed that up – in the wake of Mr Ri’s latest remarks – by saying that it would provide President Trump with options to deal with North Korea if its provocation continue. “If North Korea does not stop their provocative actions, you know, we will make sure that we provide options to the President to deal with North Korea,” Pentagon spokesman Colonel Robert Manning said.
Mr Ri’s comments echoed those of many in the Trump administration regarding North Korea’s burgeoning nuclear programme.
North Korea conducted its sixth nuclear test earlier this month, and has reportedly developed missiles capable of reaching the US mainland. The country has repeatedly threatened to use its nuclear weapons on the US if provoked and has said it is preparing rockets to fire at the territory of Guam.
Mr Trump has responded to the situation by threatening to send “fire and fury” to North Korea if the threats did not cease. In his speech to the United Nations last week, Mr Trump threatened to “totally destroy” the country, and referred to Mr Kim as “Rocket Man”.
Mr Ri responded by saying that it was now “inevitable” that North Korea would target the US mainland with its rockets. The Foreign Minister has also called Mr Trump “a mentally deranged person full of megalomania and complacency” who was trying to turn the UN into a “gangsters’ nest.”
Mr Kim took the highly unusual step of responding to Mr Trump’s UN speech himself, rather than releasing a statement from the regime through state-owned news channels. In his speech, Mr Kim said he would “surely and definitely tame the mentally deranged US dotard with fire”.
North Korea recently launched two separate missiles over Japan, demonstrating their growing military capability. The UN has implemented increasingly stringent sanctions on the country, capping their oil imports, banning textile exports, and barring countries from giving work visas to North Korean citizens.
“Enough is enough,” US ambassador Nikki Haley told the UN Security Council earlier this month. “War is never something the United States wants. We don’t want it now. But our country’s patience is not unlimited.”
While China – North Korea’s largest trading partner – and Russia have both voted for the sanctions as part of the UN Security Council, both nations have called for a non-military solution. Mr Trump has repeatedly called on China to do more to rein in the regime in Pyongyang, while Beijing and Moscow have put forward a proposal that North Korea halt its nuclear programme in return for the US and South Korea stopping military drills that Pyongyang sees as a provocation.
Asked how concerned China was the war of words between Mr Trump and North Korea could get out of control, Foreign Ministry spokesman Lu Kang described the situation as highly complex and sensitive.
It was vitally important everyone strictly, fully and correctly implemented all North Korea related UN resolutions, Mr Lu said, resolutions which call for both tighter sanctions and efforts to resume dialogue.
All sides should “not further irritate each other and add oil to the flames of the tense situation on the peninsula at present”, Mr Lu told a daily news briefing.
Speaking to Theresa May by telephone, Chinese President Xi Jinping repeated Beijing’s position that the North Korean issue should be resolved peacefully via talks, state media said.
China hoped Britain can play a constructive role in easing the situation and pushing for a resumption in talks, Xi said. Ms May, like some other US allies, has pushed for China to do more on North Korea.
But it is clear that the international community at large is wary of the duelling statements being issued by both Pyongyang and Washington and the potential for a costly mistake.
United Nations Secretary-General Antonio Guterres warned following Mr Ri’s remarks that a rise in rhetoric between North Korea and the United States increases the risk of miscalculations.
“Fiery talk can lead to fatal misunderstandings,” UN spokesman Stéphane Dujarric said. “The only solution for this is a political solution,” he added.
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