North Korean leader Kim Jong-un has declared he will "settle accounts" with Washington for threatening him with nuclear-capable stealth bombers.
An increasingly bullish Kim Jong-un said he would "press the red button" and was pictured in a war room with maps in the background plotting the trajectories of missiles targeting American cities.
A few hours after his latest call to arms, thousands of North Koreans rallied in the main square in Pyongyang, chanting "Death to the US imperialists" and "Sweep away the US aggressors", according to Associated Press, which has a bureau in Pyongyang.
The threats from North Korea came hours after two B2 stealth bombers flew over the Korean peninsula, a move that demonstrated, according to the Pentagon, that America was capable of conducting "long-range precision strikes quickly and at will".
Russia warned yesterday that North Korea and America were engaging in a dangerous game of brinkmanship that could spiral out of control.
"We are opposed to any steps from any side that increase tensions," said Sergei Lavrov, the Russian foreign minister.
He suggested the situation on the Korean peninsula was being inflamed, not only by the warmongering of Pyongyang but by the shows of military strength in recent weeks by America and South Korea.
"We are concerned that alongside an adequate reaction from the Security Council and the collective reaction from the international community, there are unilateral steps being taken around North Korea that manifest themselves in a build-up of military activity," said Mr Lavrov.
"We may simply let the situation slip out of our control and it will slide into a vicious circle spiral."
South Korea said yesterday that it had detected increased activity in various North Korean military units.
"We believe they are taking follow-up steps," said Kim Min-seek, a defence ministry spokes-man. "South Korean and American intelligence authorities are closely watching whether North Korea is preparing its short-, medium- and long-range missiles, including its Scud, Rodong and Musudan."
He acknowledged, however, that much of the rhetoric from Kim Jong-un was "psychological" posturing.
Russia also said it would judge the situation on the "specific" actions of the various sides, not on the sabre- rattling from Pyongyang and Washington.
Hugo Swire, the British Foreign Office minister, suggested that despite the bellicose rhetoric, the situation in North Korea was stabilising.
"In terms of military build-up and so on, it seems we are through the worst," he said.
"The regime is very unpredictable, but it seems we are coming down from the heights of the past few weeks".
Meanwhile, a senior North Korean tourism official has reassured Chinese tour operators that the country is not on the brink of war.
Kim To-jun reportedly said: "Do not worry. There will be no war on the Korean peninsula, so send as many tourists as possible."
Air Koryo, the country's airline, will begin flying from Beijing to Pyongyang five days a week next month.
"We have not had any disruption to our tours," said Simon Cockerell of Koryo Tours. Our next tour group is going in on April 4." (© Daily Telegraph, London)