North Korean leader Kim Jong Un. KCNA/ via REUTERS North Korea's foreign minister said that President Donald Trump through his recent tweets had "declared a war" and that the country could shoot down US strategic bombers even if they were not in its airspace, according to Reuters' Michelle Nichols.

Speaking to reporters in New York on Monday, Ri Yong Ho pointed to one of Trump's tweets that said Ri and Kim Jong Un, the country's leader, "won't be around much longer" if the North continued its nuclear provocations as constituting a declaration of war.

The White House press secretary, Sarah Huckabee Sanders, later Monday rejected North Korea's claim.

"We've not declared war on North Korea," Sanders told reporters during the White House daily briefing. "Frankly, the suggestion of that is absurd."

However, the US and North Korea have technically been at war since June 1950, as the Korean War ended in 1953 with a cease-fire rather than a peace treaty. It's unclear what North Korea means by saying Trump has declared war anew.

"Since the United States declared war on our country, we will have 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," Ri said.

Trump told the UN General Assembly last week that if the US were "forced to defend itself or its allies," it would "have no choice but to totally destroy North Korea." He also called Kim a "rocket man" who was "on a suicide mission for himself and for his regime."

North Korea responded in a statement: "If Trump thinks that he would bring North Korea, a nuclear power, to its knees through nuclear war threat, it is a big miscalculation and ignorance."

Trump and Kim have been locked in a war of words since Trump threatened in August to respond to further North Korean provocations with "fire and fury."

A US Air Force B-1B Lancer bomber during a training exercise near North Korea's border. South Korean Defense Ministry via Getty

The US Air Force this weekend flew B-1B Lancer bombers, a supersonic aircraft, near North Korea's coast. It's unclear whether North Korea has the capacity to down such an advanced jet.

In response to North Korea's threat against US planes and the prospect of renewed war, Lt. Col. Christopher Logan, a Pentagon spokesman, told Business Insider that the Defense Department was "ready to provide military response options for the president."

"We have the capability to respond to any threat from North Korea," Logan said, adding that it was "standard policy that our forces always maintain the right to self-defense."

North Korea has also recently threatened to fire a salvo of missiles at Guam, a US territory in the Pacific, and fire a nuclear-tipped missile into the Pacific Ocean.