The White House has dismissed North Korea's claim that a tweet by Donald Trump amounted to a declaration of war. White House spokeswoman Sarah Huckabee Sanders said the US had not "declared war" on Pyongyang.
The Trump administration also clarified yesterday that it was not seeking to overthrow North Korea's government after President Trump tweeted that its leader Kim Jong Un "won't be around much longer".
Pyongyang interpreted that tweet as a declaration of war.
In a speech last week to the United Nations General Assembly, Trump said if the US was forced to defend itself against North Korea, "we will have no choice but to totally destroy" the country. The US and North Korea agreed to an armistice after the 1950-1953 Korean War, not a peace treaty. Because of that, they are still technically at war.
The Trump administration also said it was not advocating regime change in North Korea.
North Korea's top diplomat, foreign minister Ri Yong Ho, responded to that at the United Nations, telling reporters it was a declaration of war against his country by the United States, and that the North had the right to shoot down US warplanes in international airspace.
A senior administration official said yesterday that the US policy was not regime change.
Mr Ri told reporters that Mr Trump's statement gives North Korea "every right" under the UN Charter to take counter-measures, "including the right to shoot down the United States strategic bombers even though they're not yet inside the airspace border of our country".
Mr Trump's tweet on Saturday said: "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!"
Mr Ri said: "The question of who won't be around much longer will be answered then."
Meanwhile, Venezuela's top diplomat has said Mr Trump acted like "the world's emperor" at the UN General Assembly.
Foreign Minister Jorge Arreaza's speech at the assembly came a day after Mr Trump signed a travel ban affecting some Venezuelan officials, and nearly a week after he denounced turmoil-racked Venezuela's "corrupt regime" in his own address to the UN. "As if he were the world's emperor, the president of the United States, Donald Trump, used this podium built for peace to announce wars, total destruction of member states and coercive measures, threatening and judging as if he had absolute, dictatorial powers over the sovereign member states of our organisation," Mr Arreaza said.
Invoking former Venezuelan President Hugo Chavez's famous quip that the podium "smells like sulphur" after then-US President George W Bush addressed the assembly in 2006, Mr Arreaza said: "It's still valid."
Venezuela's foreign ministry denounced the travel restrictions as a form of "political and psychological terrorism".
Mr Arreaza said at a news conference that it's "an unfounded strategy to soften the public opinion and to try to make a case against Venezuela".
He said his country is "looking for dialogue" with the Trump administration.
"For the moment, it has not been possible, but the will is there," Mr Arreaza said. "But, I insist, if they attack us in whatever area, we will respond strongly in defence of our homeland, of our people."