Donald Trump has warned Kim Jong-un that if the Pacific island of Guam or any other US territory is attacked, the North Korean leader "will truly regret it" - the latest round in his battle of words with isolated regime over its nuclear threat.

"This man will not get away with what he is doing," Mr Trump said. "If he utters one threat in the form of an overt threat ... or if he does anything with respect to Guam, or any place else that is an American territory or an America ally, he will truly regret it and he will regret it fast."

The President issued the threat in remarks to the press that has accompanied him on his extended vacation at his golf resort in New Jersey. When asked about his tweet earlier on Friday saying that US military solutions are "locked and loaded" should North Korea threaten the US, Mr Trump said that he's sure the North Koreans know what he meant.

"Those words are very, very easy to understand," he said.

Speaking later after a meeting meeting with US Secretary of State Rex Tillerson and US Ambassador to the United Nations Nikki Haley, Mr Trump said that both Japan and South Korea - the two allies most threatened by any potential North Korean aggression - would be "very happy" with what the US is doing. He noted then that the situation with North Korea is very dangerous, but that "no one loves a peaceful solution more than President Trump".

Mr Trump and Mr Kim have been engaged in an escalating duel of spoken threats in recent days, although the diplomatic crisis was sparked after North Korea launched two tests of Intercontinental Ballistic Missiles (ICBMs) last month. Pyongyang claimed that the range of the second missile meant they could now reach the US, which set officials on edge before an intelligence report indicated that North Korea had also successfully miniaturised nuclear weapons that would fit within one of their missiles.

Those actions prompted the UN Security Council to place severe sanctions on North Korea, leading the Asian country to say they would exact revenge for the economic losses. Mr Trump then threatened "fire and fury" if North Korea kept on moving toward their nuclear missile goals, and if they kept on threatening the US and its territories.

In pictures: North Korea military drill Show all 8 1 /8 In pictures: North Korea military drill In pictures: North Korea military drill North Korea's leader Kim Jong Un watches a military drill marking the 85th anniversary of the establishment of the Korean People's Army (KPA) KCNA/Handout via REUTERS In pictures: North Korea military drill A military drill marking the 85th anniversary of the establishment of the Korean People's Army (KPA) is seen in this handout photo by North Korea's Korean Central News Agency (KCNA) KCNA/Handout via REUTERS In pictures: North Korea military drill A military drill marking the 85th anniversary of the establishment of the Korean People's Army (KPA) is seen in this handout photo by North Korea's Korean Central News Agency (KCNA) KCNA/Handout via REUTERS In pictures: North Korea military drill A military drill marking the 85th anniversary of the establishment of the Korean People's Army (KPA) KCNA/Handout via REUTERS In pictures: North Korea military drill A military drill marking the 85th anniversary of the establishment of the Korean People's Army (KPA) KCNA/Handout via REUTERS In pictures: North Korea military drill This image made from video of still images broadcast in a news bulletin by North Korea's KRT, shows what was said to be a 'Combined Fire Demonstration' held to celebrate the 85th anniversary of the North Korean army, in Wonsan, North Korea. KRT via AP Video In pictures: North Korea military drill This image made from video of still images broadcast in a news bulletin by North Korea's KRT, shows what was said to be a 'Combined Fire Demonstration' held to celebrate the 85th anniversary of the North Korean army, in Wonsan, North Korea. KRT via AP Video In pictures: North Korea military drill This image made from video of still images broadcast in a news bulletin by North Korea's KRT, shows what was said to be a 'Combined Fire Demonstration' held to celebrate the 85th anniversary of the North Korean army, in Wonsan, North Korea. KRT via AP Video

North Korea responded by called their "fire and fury" remarks "nonsense" but said that they are planning on launching missiles with 25 miles of Guam by the end of the month, as warning shots - nothing on land will be targeted.

“Trump is driving the situation on the Korean peninsula to the brink of a nuclear war, making such outcries as 'the US will not rule out a war against the DPRK [North Korea],'” the state news agency KCNA said in another statement early on Friday. The North has also repeatedly said that regular military exercises between the US and South Korea are a provocation.

That came just before Mr Trump's tweet which read: "Military solutions are now fully in place, locked and loaded, should North Korea act unwisely. Hopefully Kim Jong Un will find another path!"

In his tweet, Mr Trump did not specify whether the solutions were preemptive or reactive, but on Thursday US Defence Secretary James Mattis said the military "was ready" to respond to any attack, but that the US preferred a diplomatic solution.

Officials on Guam, a Pacific island that is home to a population of more than 160,000, have issued advisories of how to deal with a missile attack. The island, which hosts two major US military bases, is home to many US military families.

"Do not look at the flash or fireball as it can blind you," the guidelines said. "Take cover behind anything that might offer protection."

Mr Trump's tweet attracted immediate criticism from opponents. Ben Rhodes, a former foreign policy adviser to Barack Obama, said: "This isn't a video game. Hundreds of thousands of lives at stake in war with NK. Was this statement signed off on by anyone?

"Was this statement coordinated with South Korea and Japan, our allies who are at enormous risk in conventional conflict with North Korea?"

A number of nations have called for calm, with officials from Russia and Germany speaking out on Friday.

In Moscow, Russian Foreign Minister Sergei Lavrov urged Pyongyang and Washington to sign up to a previously unveiled joint Russian-Chinese plan under which North Korea would freeze missile tests and the United States and South Korea would impose a moratorium on large-scale military exercises. Neither the United States nor North Korea has embraced the plan.

Mr Lavrov said the risks of a military conflict over North Korea's nuclear program are very high and Moscow is deeply worried by the threats from Washington and Pyongyang.

“Unfortunately, the rhetoric in Washington and Pyongyang is now starting to go over the top,” Mr Lavrov said on live state television at a forum for Russian students. “We still hope and believe that common sense will prevail.”

German Chancellor Angela Merkel said there is no military solution to the dispute, adding that “an escalation of the rhetoric is the wrong answer.”

“I see the need for enduring work at the UN Security Council ... as well as tight cooperation between the countries involved, especially the US and China,” Ms Merkel said.

Mr Trump later indicated that he wasn't sure what Ms Merkel meant when saying no military option was available, and indicated that he believed she may have been referring to her own country instead of his.

When the members of the UN Security Council voted last week for new sanctions aimed at cutting North Korea's exports, both China - Pyongyang's biggest trading partner - and Russia backed the new measures. But Mr Trump has repeatedly called on China to pressure Mr Kim into halting his rapidly advancing nuclear programme, and he was due to speak to China's President Xi Jinping by telephone late on Friday night.

With tensions flaring, South Koreans are preparing for the worst. In markets in Seoul and elsewhere, they're stocking up on ready-to-eat meals that could be relied on in an emergency. The government is planning to expand national civil defence drills on August 23.

The tensions have already impacted global market, which saw a loss of $1tn Friday, with investors taking refuge in the yen, Swiss francs, gold, and government bonds.

Mr Trump told reporters before a security briefing with top advisers on Thursday: “We’re backed 100 per cent by our military, we’re backed by everybody and we’re backed by many other leaders.

“And I noticed that many senators and others came out today very much in favour of what I said. But if anything that statement may not be tough enough.”

The President said the US has been negotiating with North Korea for 25 years and that his nation “would always consider negotiations”. but blamed his predecessors for a lack of progress.

Bill Clinton, he said, was “weak and ineffective”, while Mr Obama “didn’t even want to talk about it,” he added.

It emerged on Friday that Joseph Yun, the US envoy for North Korea policy, has engaged in back-channel diplomacy for several months with Pak Song Il, a senior diplomat at Pyongyang's UN mission, on the deteriorating relations and the issue of Americans imprisoned in North Korea, the Associated Press reported.

The US State Department previously said Mr Yun had met with Mr Pak in New York and travelled to Pyongyang in June to discuss the release of Otto Warmbier, the American student imprisoned in North Korea who died soon after his return to the United States.

The State Department have said that the Trump administration are speaking with “one voice” on the issue of North Korea, but Mr Trump's unfiltered tweets and statements have sometimes contradicted more moderate lines taken by senior members of his cabinet.

Mr Trump's language has raised concerns back in the United States that the President will lead the US into an unnecessary military conflict. Sixty Democratic members of Congress have signed a letter of concern to Mr Tillerson - whose department says it is unified with the West Wing.

"These statements are irresponsible and dangerous, and also senselessly provide a boon to domestic North Korean propaganda which has long sought to portray the United States as a threat to their people," they wrote.