South Korea's President Moon Jae-in has called on the US to help bring about a "peaceful solution" to the deepening diplomatic crisis with its northern neighbour after days of threat and counter threat.

Donald Trump's recent comments that the US military is "locked and loaded" to deal with North Korea are part of an escalating war of words, with that warning coming in response to Pyongyang's threat to attack the US territory of Guam, a small Pacific island about 3,540 kilometres (2,200 miles) southeast of the Korean peninsula.

“There must be no more war on the Korean peninsula. Whatever ups and downs we face, the North Korean nuclear situation must be resolved peacefully,” Mr Moon told a meeting of senior aides and advisers. “I am certain the United States will respond to the current situation calmly and responsibly in a stance that is equal to ours,” he said.

Separately, Mr Moon met with the top US military officer, Chairman of the Joint Chiefs of Staff General Joseph Dunford, in Seoul, who said the US wants to peacefully resolve a deepening standoff with North Korea but is also ready to use the “full range” of its military capabilities in case of provocation and if a diplomatic push or sanctions did not work.

The comments by General Dunford – made during a trip that will also include visits to Japan and China – appeared to be an attempt to ease anxiety over tit-for-tat threats between Mr Trump and North Korea while also showing a willingness to back up The President's warnings if need be.

“We are seeking a peaceful resolution to the crisis,” General Dunford told local reporters. He added he aims to use the Asia trip to get a “sense what the temperature is in the region”. He also will discuss military options in the event the “diplomatic and economic pressurisation campaign” fails.

He earlier told his South Korean counterparts that America is ready “to use the full range of military capabilities to defend our allies and the US homeland”, according to military spokesman Captain Darryn James.

That point was reinforced by US Defence Secretary Jim Mattis later in the day. “If they fire at the United States, it could escalate into war very quickly,” Mr Mattis said.

Mr Mattis added the United States would know the trajectory of a North Korean missile “within moments” and if a missile is assessed to be hitting Guam, “we will take it out”.

The latest tension between the US and North Korea has been sparked by worries that the North's nuclear weapons programme is nearing the ability to target the US mainland. Pyongyang conducted two intercontinental ballistic missile (ICBM) tests in July and there have been reports that US intelligence agencies belive the regime of North Korean leader Kim Jong-un have successfully miniaturised a nuclear weapon that could potentially fit on such a missile.

Seoul is within easy striking distance of Pyongyang. The US also has about 28,500 troops stationed there at any given time.

The North has accused the US of mobilising a huge number of weapons and troops for annual military drills with South Korea that begin later this month. Pyongyang claims the drills are war preparation and has signalled it would back down in the face of any action by the US..

“What matters is that if a second conflict [on the peninsula] erupts, that cannot help but lead to a nuclear war,” the North's official Korean Central News Agency said in a commentary. “We are closely monitoring every move by the United States.”

The commentary said that about 3.5 million young students and workers have volunteered to join or rejoin the army because of a possible confrontation with the United States.

Scott Snyder, Senior Fellow for Korea Studies and Director of the Programme on US-Korea Policy at the Council on Foreign Relations told The Independent that if Pyongyang attacks Guam, it would be "suicidal, and Kim Jong-un is not suicidal".

But, the threat is not an empty one despite the small chance of follow-through. "If you are a US security planner ... You still have to prepare for that possibility," Mr Snyder noted.

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

To that end, General Dunford said prior to his arrival in Seoul that "as a military leader, I have to make sure that the President does have viable military options in the event that the diplomatic and economic pressurisation campaign fails".

Mr Mattis and Secretary of State Rex Tillerson have also penned an opinion piece in the Wall Street Journal.

They say they called the Trump administration policy a reaction to previous administrations' "failed policy of ‘strategic patience’, which expedited the North Korean threat".

They called the approach "strategic accountability" which essentially prompts China to exercise its economic power over Pyongyang as a method of avoiding military options.

Tuesday marks the anniversary of Japan's expulsion from the Korean peninsula, a rare holiday celebrated by both the North and the South. Mr Moon and Mr Kim, who has not been seen publicly for several days, are both expected to make addresses on their respective sides of the heavily militarised border.

US National Security Adviser HR McMaster and CIA Director Mike Pompeo have both said they do not foresee a war with North Korea despite the President's fiery rhetoric.

Mr Trump has repeatedly urged China, the North's main ally and trading partner, to do more to rein in its neighbour, often linking Beijing's efforts to comments around US-China trade. China strenuously rejects linking the two issues.

On Monday, Mr Trump signed a presidential memorandum authorising an investigation into China's alleged theft of American intellectual property, declaring it “one big move”.

The order directs US Trade Representative Robert Lighthizer to determine whether to investigate Chinese trade practises that force US companies operating in China to turn over intellectual property.

“This is just the beginning,” Mr Trump added.

Chinese Foreign Ministry spokeswoman Hua Chunying had earlier said that Beijing has made clear many times the essence of China-US trade and business ties is mutual benefit and that there is no future in any trade war between China and the United States.

“The (Korean) peninsula issue and trade and business issues are in a different category from each other,” Ms Hua added. “On these two issues, China and the United States should respect each other and increase cooperation. Using one issue as a tool for exerting pressure on another is clearly inappropriate.”