Ri, who attended this year’s UN General Assembly session, said the international community had hoped that a “war of words” would “not turn into real actions”.

“However, last weekend, Trump claimed our leadership would not be around much longer,” Ri said. “He declared a war on our country.”

Alarm over Pyongyang’s nuclear and ballistic missile programmes dominated this year’s gathering of world leaders at the United Nations, amid fears the heated rhetoric could accidentally trigger a war.

Those fears were further heightened after US bombers flew off the coast of North Korea on Saturday.

“Since the United States declared war on our country, we will have every right to take countermeasures including the right to shoot down US strategic bombers even when they are not yet inside the airspace border of our country,” Ri said. “The question of who won’t be around much longer will be answered then.”

The foreign minister said the statement from Trump was “clearly a declaration of war” even if it came from the US president. Under the US Constitution, Congress is the sole power that can declare war.

The White House disputed the Ri’s interpretation of Trump’s sabre rattling.

“We have not declared war against North Korea and frankly the suggestion of that is absurd,” said White House spokeswoman Sarah Huckabee Sanders.

China on Tuesday urged North Korea and the US to stop their escalating war of words and sit down for talks.

The comments from foreign ministry spokesman Lu Kang reinforce China’s position that all sides should avoid provoking each other.

“A war on the Korean Peninsula will have no winner, which will also be a tragedy for regional countries,” Lu told reporters at the daily briefing. “Given our consistent opposition to the war and chaos on the peninsula, we totally disapprove of an escalation of the war of words between the US and North Korea.”

South Korea also appealed for an easing of tensions, with foreign minister Kang Kyung-wha saying that further provocations can be expected from Pyongyang but must not be allowed to get out of control.

“It is imperative that we, Korea and the US together, manage the situation ... to prevent further escalation of tensions or any kind of accidental military clashes which can quickly go out of control,” Kang said in Washington.

South Korea has reacted with unease to Trump’s threat to “totally destroy” North Korea as its densely-populated capital Seoul is located just 35 miles from the demilitarised zone separating the Korean peninsula.

In his UN address last week, Trump delivered the blunt threat and derided leader Kim Jong-un as “Rocket Man” and declared he was “on a suicide mission.”

Kim hit back with a personal attack on Trump, branding him “mentally deranged” and a “dotard” and warning he would “pay dearly” for his threat.

There have been repeated appeals for calm from the United Nations, Russia and China.

Asked about the North Korean minister’s latest remarks, UN spokesman Stephane Dujarric acknowledged the dangerous spike in tensions, saying: “When you have the rise of tension, the rise of rhetoric, so does the risk of miscalculation.”

North Korea in recent weeks detonated its sixth nuclear bomb and has test-fired intercontinental missiles – saying it needs to defend itself against hostility from the US and its allies.

Just hours before Ri took the UN podium on Saturday, US bombers flew off the east coast of North Korea, the furthest north of the demilitarised zone that any US aircraft has flown this century.

The Pentagon described the mission as a “demonstration of US resolve and a clear message that the president has many military options to defeat any threat”.

A Pentagon spokesman stressed on Monday that the bombers flew in international airspace. “So we have the right to fly, sail and operate and we are legal permissible around the globe,” he said.

In his UN address, Ri warned that Trump’s threat to destroy North Korea made “our rockets’ visit to the entire US mainland all the more inevitable.

The bellicose rhetoric comes as international alarm mounts over Pyongyang’s weapons ambitions – including a suggestion by Ri last week that the country is considering detonating an H-bomb over the Pacific.

US Defence Secretary Jim Mattis has said such a move would be a “shocking display of irresponsibility.”

As tensions over North Korea reached fever-pitch, Japanese Prime Minister Shinzo Abe called a snap election, hoping to capitalise on a boost in the polls that some say is linked to his hawkish stance toward Pyongyang.