North Korea has accused the US of declaring war and threatened to shoot down US bombers.
The threat was issued by North Korea's foreign minister, Ri Yong-ho, to reporters in New York.
Ri said that North Korea can shoot the planes down, even if they aren't passing through North Korean airspace.
Foreign Minister Ri Yong Ho said: "The whole world should clearly remember it was the U.S. who first declared war on our country.
"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's assertion that North Korea is merely responding to US aggression has been a familiar refrain over recent weeks, with Pyongyang representatives regularly saying that Donald Trump is the aggressor in his ongoing spat with the country.
Last week Alejandro Cao de Benos, North Korea's unofficial ambassador to Europe, told talkRADIO that North Korea will never fire first but warned Trump "we're ready to fight."
Tension between Pyongyang and Washington has been rising steadily over recent months. Trump has accused North Korean leader Kim Jong-un of being a "madman" and suggested he is on a "suicide mission" while Kim has called Trump a "dotard."
North Korea has conducted several missile tests over the course of this year, prompting the US government to warn of severe reprisals if the rogue Communist state commits any act of overt aggression towards America.