North Korea said on Wednesday it is "carefully examining" a plan to strike the U.S. Pacific territory of Guam with missiles, just hours after U.S. President Donald Trump told the North that any threat to the United States would be met with "fire and fury".
A spokesman for the Korean People's Army, in a statement carried by the North's state-run KCNA news agency, said the strike plan will be "put into practice in a multi-current and consecutive way any moment" once leader Kim Jong Un makes a decision.
In another statement citing a different military spokesman, North Korea also said it could carry out a pre-emptive operation if the United States showed signs of provocation.
Earlier Pyongyang said it was ready to give Washington a "severe lesson" with its strategic nuclear force in response to any U.S. military action.
Washington has warned it is ready to use force if need be to stop North Korea's ballistic missile and nuclear programs but that it prefers global diplomatic action, including sanctions.
The consequences of any U.S. strike would potentially be catastrophic not only for North Koreans but also South Korea, Japan and the thousands of U.S. military personnel within range of any North Korean retaliatory strikes.
"North Korea best not make any more threats to the United States. They will be met with fire and fury like the world has never seen," Trump told reporters at the Trump National Golf Club in Bedminster, New Jersey.
The U.N. Security Council unanimously imposed new sanctions on North Korea on Saturday over its continued missile tests, that could slash the reclusive country's $3 billion annual export revenue by a third.
North Korea has made no secret of plans to develop a nuclear-tipped missile able to strike the United States and has ignored international calls to halt its nuclear and missile programs.
It says its intercontinental ballistic missiles (ICBMs) are a legitimate means of defense against perceived U.S. hostility. It has long accused the United States and South Korea of escalating tensions by conducting military drills.
U.S. stocks closed slightly lower after Trumps comment, while a widely followed measure of stock market anxiety ended at its highest in nearly a month. The U.S. dollar index pared gains and the safe-haven yen strengthened against the U.S. currency.
The United States has remained technically at war with North Korea since the 1950-53 Korean conflict ended in an armistice rather than a peace treaty. The past six decades have been punctuated by periodic rises in antagonism and rhetoric that have always stopped short of a resumption of active hostilities.
Tensions have risen since North Korea carried out two nuclear bomb tests last year and two ICBM tests last month.
The Trump administration's attempts to pressure North Korea into abandoning its nuclear and missile ambitions have so far gained little traction.
U.S. Defense Secretary Jim Mattis has warned of an "effective and overwhelming" response against North Korea if it chose to use nuclear weapons but has said any military solution would be "tragic on an unbelievable scale."
The United States has 28,500 troops in South Korea to guard against the North Korean threat. Japan hosts around 54,000 U.S. military personnel, the U.S. Department of Defense says, and tens of thousands of Americans work in both countries.
Seoul is home to a population of roughly 10 million, within range of massed pre-targeted North Korean rockets and artillery, which would be impossible to destroy in a first U.S. strike.
The Washington Post reported on Tuesday that North Korea has successfully produced a miniaturized nuclear warhead that can fit inside its missiles, according to a confidential U.S. intelligence assessment.
But U.S. intelligence officials told Reuters that while North Korea has accelerated its efforts to design an ICBM, a miniaturized nuclear warhead, and a nosecone robust enough to survive reentry through the Earths atmosphere from space, there is no reliable evidence that it has mastered all three, much less tested and combined them into a weapon capable of hitting targets in the United States.
The bottom line is that its almost impossible, given the amount and reliability of available intelligence, to reach a high-confidence assessment of the Norths nuclear capabilities, a U.S. intelligence official said.
U.S. intelligence officials, who spoke on condition of anonymity, also said there is no certainty about the number of nuclear warheads North Korea has assembled, with estimates ranging from 20 to as many as 60 and most experts leaning toward the lower end of that range.
North Korea's ICBM tests last month suggested it was making technical progress, Japan's annual Defence White Paper warned.
"It is conceivable that North Korea's nuclear weapons programme has already considerably advanced and it is possible that North Korea has already achieved the miniaturisation of nuclear weapons and has acquired nuclear warheads," it said.
War of words
On Monday, U.S. Secretary of State Rex Tillerson held the door open for dialogue, saying Washington was willing to talk to Pyongyang if it halted its missile test launches.
Still, he maintained the pressure, urging Thailand on Tuesday for more action against Pyongyang.
Former U.S. diplomat Douglas Paal, now with the Carnegie Endowment for International Peace think tank in Washington, said Trump should not get into a war of words with Pyongyang.
It strikes me as an amateurish reflection of a belief that we should give as we get rhetorically. That might be satisfying at one level, but it takes us down into the mud that we should let Pyongyang enjoy alone, said Paal, who served as a White House official under previous Republican administrations.
South Korea reiterated further United Nations resolutions against Pyongyang could follow if it did not pull back.
"North Korea should realize if it doesn't stop its ... provocations, it will face even stronger pressure and sanctions," Defense Ministry spokesman Moon Sang-gyun told a news briefing. "We warn North Korea not to test or misunderstand the will of the South Korea-U.S. alliance."
Lockheed Martin Corp, the Pentagon's No. 1 weapons supplier, said on Tuesday its customers are increasingly asking about missile defense systems.
"The level of dialogue ... is now at the prime minister and minister of defense level," Tim Cahill, the vice president of Lockheed's Air and Missile Defense business, told Reuters.