North  Korea’s foreign minister escalated tensions with the  United States on  Monday, saying that President Trump’s threatening  comments about the  country and its leadership were “a declaration of  war” and that North  Korea had the right to shoot down American  warplanes, even if they are  not in North Korean air space.
“The  whole world should clearly remember it was the U.S. who first  declared  war on our country,” the foreign minister, Ri Yong-ho, told  reporters as  he was leaving the United Nations after a week of General  Assembly  meetings in New York.
“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.”
Referring to Mr. Trump’s assertion that the North Korean leadership 
may not “be around much longer,” Mr. Ri said that the question of “who would be around much longer will be answered” by North Korea.
Mr. Ri, speaking two days after American warplanes flew close to the   North’s coast, added that “in light of the declaration of war by Trump,   all options will be on the operations table of the supreme leadership”   of North Korea.
North Korea had already deemed 
Mr. Trump’s threat at the United Nations — to 
“totally destroy” North Korea if the United States were forced to defend itself or its allies — a declaration of war.
The  North Korean leader, Kim Jong-un, said last week: “Now that Trump  has  denied the existence of and insulted me and my country in front of  the  eyes of the world and made the most ferocious declaration of a war  in  history that he would destroy the D.P.R.K. [Democratic People’s  Republic  of Korea], we will consider with seriousness exercising of a   corresponding, highest level of hard-line countermeasure in history.”
The  Pentagon said on Saturday that the Air Force had sent B-1B bombers  and  F-15C fighters over waters north of the Demilitarized Zone that   separates the two Koreas, in response to what it called the North Korean   government’s “reckless behavior.”
It  was the farthest north “any U.S. fighter or bomber aircraft have  flown  off North Korea’s coast in the 21st century,” Dana W. White, the  Defense  Department’s chief spokeswoman, said in a statement.