A man watches a TV news program showing file footage of North Korean leader Kim Jong-un. Credit:AP North Korea has displayed the Musudan at its military parades and is believed to have supplied assembly kits for the missile to Iran, but it had never tested this model of missile before. Jeffrey Lewis, head of the East Asia program at the James Martin Centre for Non-proliferation Studies in California, said that the failure would "reinforce the persistent denial" about North Korea's capabilities. "But in fact, they will have learned a lot from this launch. Not as much as they would have learned if it had succeeded, but still something," Dr Lewis said. The Musudan uses the same sort of engine as a submarine-launched ballistic missile that North Korea tested last year but which also failed.

"Clearly they have a problem, but maybe next time it will work. It took them a couple of launches to get the Taepodong-2 going," he said, referring to the ballistic missile technology that has now put two North Korean satellites into orbit. In a string of increasingly ferocious threats through its state media, Kim Jong-un's regime has been vowing missile launches and nuclear attacks, often with specific threats to blow up New York, Washington and the South Korean presidential Blue House. At the same time, North Korea has been making a series of claims about technological advances, from building solid-fuel rocket engines to miniaturising nuclear warheads. The regime recently claimed that it could send a nuclear-tipped missile to the US mainland. Although this has not been proven, US military officials and non-proliferation experts say that North Korea is clearly working toward this goal. The Musudan test could be part of this program. At a hearing of a Senate's armed services subcommittee this week, Brian McKeon, a senior Pentagon official, said that North Korea's weapons and missile programs posed a growing threat to the USand its allies in East Asia.

North Korea is "seeking to develop longer-range ballistic missiles capable of delivering nuclear weapons to the United States and continues efforts to bring [a road-mobile intercontinental ballistic missile] to operational capacity", he said. Although an untested long-range missile was unlikely to be reliable, North Korea's successful satellite launches showed it was mastering the technologies that would be needed, Mr McKeon said. Since Mr Kim ordered his military to conduct a fourth nuclear test in January – which North Korea claimed as a hydrogen bomb explosion, although outside experts are highly sceptical of this – there has been a steady stream of projectiles emanating from North Korea. In February, Mr Kim oversaw the launch of what North Korean said was a satellite launch vehicle but which was widely viewed as part of an intercontinental ballistic missile program. Since then, there have been numerous short-range missile launches and rockets fired into the Sea of Japan. North Korea is banned by UN Security Council resolutions from launching ballistic missiles or carrying out nuclear tests, but it continues to do so.

The international community has responded to North Korea's latest provocations with tough sanctions aimed at cutting off the state's ability to procure parts and finance its weapons of mass destruction program. This push coincided with two-month-long drills between US and South Korean militaries, during which they are practising their response to the collapse of North Korea. The drills, which conclude at the end of this month, include computer-simulated "decapitation strikes" on the North Korean leadership. Amid this background of heightened tensions, North Korea has been preparing for two key events – the anniversary of Kim Il-sung's birthday on Friday, and the first congress of the communist Workers' Party in 36 years. Kim Il-sung, the current leader's grandfather and "eternal president" of North Korea, died in 1994, but his birthday continues to be celebrated as the "Day of the Sun" in a country that is held together by a pervasive personality cult. It is usually celebrated with great fanfare in Pyongyang, often with elaborate military events. Meanwhile, the country is in the grip of a "70-day campaign" to prepare for the congress, set for early next month for the first time since 1980. Analysts expect Mr Kim to use the event to bolster his legitimacy.

Mr Kim, who is only 33, is not only incredibly young by Korean standards, where age is revered, but did not have the kind of long preparation and introduction his father enjoyed. Kim Il-sung publicly groomed Kim Jong-il for two decades before his death, but Kim Jong-il had announced his son as his successor only a year before his death at the end of 2011. Washington Post Follow FairfaxForeign on Twitter Follow Fairfax Foreign on Facebook