N Korea considers missile strike on US Pacific territory of Guam

The sharp increase in tensions rattled financial markets and prompted warnings from US officials and analysts not to engage in rhetorical slanging matches with North Korea, which regularly threatens to destroy the United States.

North Korea said it was "carefully examining" a plan to strike Guam, which is home to about 163,000 people and a US military base that includes a submarine squadron, an airbase and a Coast Guard group.

A Korean People's Army spokesman said in a statement carried by state-run KCNA news agency the plan would be put into practice at any moment once leader Kim Jong Un makes a decision.

Guam Governor Eddie Calvo dismissed the threat and said the island was prepared for "any eventuality" with strategically placed defences. He said he had been in touch with the White House and there was no change in the threat level.

"Guam is American soil ... We are not just a military installation," Calvo said in an online video message. North Korea, which is pursuing missile and nuclear weapons programmes in defiance of UN Security Council resolutions, also accused the United States of devising a "preventive war" and said in another statement that any plans to execute this would be met with an "all-out war wiping out all the strongholds of enemies, including the US mainland".

In a small show of goodwill though, North Korea said it had released a Canadian pastor serving a life sentence there on humanitarian grounds.

Washington has warned it is ready to use force if needed to stop North Korea's ballistic missile and nuclear programmes but that it prefers global diplomatic action, including sanctions. The UN Security Council unanimously imposed new sanctions on North Korea on Saturday.

Trump issued his strongest warning yet for North Korea in comments to reporters in New Jersey on Tuesday.

"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 said.

China, North Korea's closest ally despite Beijing's anger at Pyongyang's missile and nuclear programmes, described the situation as "complex and sensitive", and urged calm and a return to talks.

"China calls on all sides to uphold the main direction of a political resolution to the Korean peninsula nuclear issue, and avoid any words or actions that may intensify the problem and escalate the situation," it said in a statement sent to Reuters, repeating its customary stance.

North Korea has made no secret of its plans to develop a nuclear-tipped missile able to strike the United States and has ignored all calls to halt its weapons programmes.

Donald Trump issued his dire threat of "fire and fury" to North Korea to send a strong message "in language that Kim Jong-un can understand", US Secretary of State Rex Tillerson has said. Tillerson sought to downplay the escalating diplomatic crisis, saying Americans "should sleep well at night"."I do not believe that there is any imminent threat" from North Korea, he added. His intervention came after Trump told North Korea's leadership it would be "met with fire and fury like the world has never seen" if it made more threats to the US. Pyongyang in turn said it was "carefully examining the operational plan for making an enveloping fire at the areas around Guam", an island in the Pacific home to around 6,000 US military personnel. Tillerson, speaking as he returned to Washington from a tour of Southeast Asia, said the President's comments were an attempt to prevent "any miscalculation" by the North."What the President is doing is sending a strong message to North Korea in language that Kim Jong-un can understand, because he doesn't seem to understand diplomatic language," the Secretary of State said.

"I think the President just wanted to be clear to the North Korean regime on the US' unquestionable ability to defend itself, will defend itself and its allies."