North Korea has ordered its military to be ready to strike US bases in Guam, Hawaii and mainland America, according to state TV.
"The Korean People's Army top command declares that all artillery troops including strategic rocket units and long-range artillery units are to be placed under Class A combat readiness," the Korean Central News Agency (KCNA) said.
The announcement came as images were released showing a new round of military exercises by the isolated state.
The still photographs show what appears to be a sea-borne assault using hovercraft and an artillery drill using multiple rocket launchers - none of which would have the capacity to reach more than a dozen or so miles.
North Korean leader Kim Jong-Un is pictured visiting troops and watching the exercise from a vantage point above the unidentified beach on the country's east coast.
The photographs, released by KCNA, are accompanied by language which matches weeks of rhetoric.
According to the news agency, Mr Kim "stressed the need to destroy and wipe away any enemy who lands on their coast through strong firepower and ordered the soldiers of the heroic Korean People's Army to display their mettle in the great war against the enemies".
"Crazy like wild wolves threatened with fire, send all of them to the bottom of the sea," he is quoted as saying.
The Pentagon later condemned the "bellicose" rhetoric, saying the United States was ready "to respond to any contingency".
The exercise and the photographs of it are a clear response to a series of month-long exercises taking place across the border in South Korea involving American and South Korean troops and naval forces.
Defence analysts have been studying the latest photographs with interest.
James Hardy, the Asia-Pacific Editor of Jane's Defence Weekly, told Sky News he had not seen hovercraft like those in the photographs before.
However, he added: "I can categorically state that multiple rocket launchers and 'long-range artillery' are not going to threaten the US mainland, Guam or Hawaii, unless they are put on a ship and sailed to within firing distance (which I doubt the North Koreans are about to do)."
It has been an uneasy few months on the Korean peninsula with rhetoric and threatening language at a level not seen for several years.
The increased tension comes as Seoul marks the third anniversary of the sinking of a South Korean warship.
On March 26, 2010, the Cheonan was torpedoed by the North Korean military with the loss of 46 sailors.
In December, North Korea launched a satellite into orbit in the tip of a rocket.
Their claim then was that this was all part of Pyongyang's legitimate right to pursue a space programme.
Few countries bought that claim, believing instead that it represented the latest move in North Korea's development of a ballistic missile programme.
The rocket launch was followed in February by an underground nuclear test and a sharp escalation in tension.
Faced with unprecedented UN sanctions, backed by his historical ally China, Mr Kim admitted the rocket launch and nuclear test were indeed all part of his ideological desire to destroy America and its allies.
Asked about the accuracy and range of rockets like that fired in December, Mr Hardy said he believed North Korea was still some way off possessing an operational missile of this type.
"It's a mish mash of fuel types and requires quite a bit of time to assemble on a purpose-built launch pad," he continued.
"The US, or anyone else, would have plenty of time to scope it out before it got airborne so its operational value is quite low even before you start talking about the challenges of placing a warhead on it."
The annulment of the armistice agreement with South Korea and repeated threats to attack the South over the past three weeks have, so far, been exposed as nothing more than bluff and bluster.
However with unattributed cyber attacks - some on defector groups from the North - in Seoul, repositioned missile defence systems on America's west coast and the presence of US B-52 bombers in the skies above the Korean peninsula, there is no doubt minds across the region and beyond are very focused on a fragile peace and an unpredictable regime.