North Korea threatens to reduce US and South Korea to 'flames and ash'

North Korea has threatened to turn Washington and Seoul into “flames and ashes”, warning of an indiscriminate “pre-emptive nuclear strike of justice” in reaction to the start of US-South Korean military drills.

Such threats have been a staple of the North Korean leader, Kim Jong-un, since he took power after his father’s death in December 2011. But they tend to increase when Washington and Seoul stage what they describe as annual defensive springtime war games.

Pyongyang says the drills, which were set to start on Monday and run to the end of April, are rehearsals for invading.

North Korea’s powerful National Defence Commission threatened strikes against targets in South Korea, US bases in the Pacific and the US mainland, saying its enemies “are working with bloodshot eyes to infringe upon the dignity, sovereignty and vital rights” of the country.

“If we push the buttons to annihilate the enemies even right now, all bases of provocations will be reduced to seas in flames and ashes in a moment,” the statement said.

A pre-emptive, large-scale military strike that would end the authoritarian rule of the Kim dynasty is highly unlikely.

There is also considerable outside debate about whether North Korea is even capable of the kind of strikes it threatens. The country makes progress with each new nuclear test, having staged its fourth in January, but many experts say North Korea’s arsenal may consist only of still-crude nuclear bombs.

There is uncertainty as to whether it has mastered the miniaturisation process needed to mount bombs on warheads and widespread doubt over whether the country has a reliable long-range missile that could deliver such a bomb to the US mainland.

But North Korea’s bellicose rhetoric raises unease in Seoul and the US, not least because of the huge number of troops and weaponry facing off along the world’s most heavily armed border, which is an hour’s drive from the South Korean capital of Seoul and its 10 million residents.

Korean animosity occasionally erupts in bloody skirmishes. Fifty South Koreans were killed in attacks in 2010 that Seoul blames on North Korea, and there are always concerns about an escalation of violence.

Relations between North Korea and Seoul and Washington have worsened since North Korea’s nuclear test in January and a long-range rocket test last month, which outsiders said was a test of banned ballistic missile technology.

The United Nations recently imposed strong new sanctions on North Korea , and South Korea has said it will announce new unilateral sanctions on Tuesday.

Similar nuclear threats by North Korea were made in 2013, around the time of the springtime military drills, after it was sanctioned by the UN over a nuclear test and long-range rocket launch.

South Korea’s military said this year’s war games will be the largest yet staged, involving 300,000 South Korean military personnel and 17,000 from the US. Analysts say one element of North Korea’s traditional anger over the drills is that they force the impoverished nation to respond with its own costly war games.

Responding to North Korea’s threat, South Korean defence ministry spokesman Moon Sang Gyun said it must refrain from a “rash act that brings destruction upon itself”.