North Korea nuclear threat: South Korea warns citizens that Pyongyang is now ready to launch a missile 'at any time'

South Korea’s warning of an 'imminent' strike comes as the North prepares to mark the April 15 birthday of the nation’s founder Kim Il-sung

A South Korean soldier walks along barricades on the road leading to North Korea at a military checkpoint in the border city of Paju (Getty Images)

A South Korean defence minister has warned that North Korea could launch a nuclear missile “at any time”, after Pyongyang completed final preparations for a weapons test.

South Korea’s warning to its citizens to prepare for an “imminent” strike comes as Pyongyang prepares to mark the April 15 birthday of the nation’s founder Kim Il-sung.

The anniversary, a major national holiday, is historically a time when the reclusive communist state seeks to draw the world's attention with dramatic displays of military power.

Last year, the days surrounding Kim Il Sung’s centennial were marked by parades of tanks, goose-stepping soldiers and missiles, as well as the failed launch of a satellite-carrying rocket widely believed by the US and its allies in the West to be a test of ballistic missile capabilities.

A subsequent test in December went off successfully, and that was followed by the country's third underground nuclear test on February 12 this year.

The resulting UN sanctions have been met with an unending string of threats and provocations from the North, raising tensions on the peninsula to their highest point since the end of the Korean War in 1953, according to some experts.

Yesterday Pyongyang advised foreign embassies to consider evacuating their citizens and warned tourists in South Korea to leave Seoul in case of an outbreak of war. But most diplomats and foreign residents appeared to be staying put.

In Seoul, the Defence Ministry official said the North appeared ready to carry out a missile launch at any time.

He said Pyongyang's military was capable of conducting multiple missile launches involving Scud and medium-range Rodong missiles, as well as a missile transported to the east coast recently. He refused to say how Seoul obtained the information.

Admiral Samuel Locklear, commander of US Pacific Command, told the Senate Armed Services Committee in Washington yesterday that he agreed with an assessment by Senator John McCain calling the tension between North Korea and the West the worst since the end of the Korean War.

“The continued advancement of the North's nuclear and missile programmes, its conventional force posture, and its willingness to resort to asymmetric actions as a tool of coercive diplomacy creates an environment marked by the potential for miscalculation,” Adm Locklear told the panel.

He said the US military and its allies would be ready if North Korea tried to strike.

Meanwhile South Korea said an initial investigation had found North Korean government agents were behind a March cyber-attack that shut down about 32,000 computers and servers at South Korean broadcasters and banks.

An official at the South's internet security agency, Chun Kil-soo, said the attack was similar to past North Korean hacking. He said investigators believe six computers in North Korea were used to access South Korean servers using more than 1,000 IP addresses overseas