Imminent attack?

South Korea's intelligence services have warned that Pyongyang could fire a medium-range missile as early as Wednesday, keeping up its defiance against the international community, while there are also new reports out of Seoul that Pyongyang is carrying out preparatory work to conduct another test of a nuclear warhead.

Though the South Korean Defense Ministry later dismissed the suggestion of an imminent nuclear test, the country's JoongAng Ilbo newspaper had reported on Monday that there are clear signs of preparations for a new test at the Punggye-ri site in the far northeast of the country, less than two months after the regime's third underground nuclear test prompted the United Nations Security Council to institute a new round of sanctions against Pyongyang.

Far from having the desired effect and forcing Kim's government to back down, however, North Korea seems keen to push the crisis to new highs.

Work at nuclear test site

"We have detected increased activity in labor forces and vehicles at the southern tunnel of the test site in Punggye-ri, where the regime has worked on maintenance for facilities since its third nuclear test in February," a senior South Korean government official told the newspaper.

"The activities appear to be similar to those before the third test, so we are closely monitoring the site," the official added.

The South Korean government has received intelligence that a fourth test was being readied in the North, the official said. "But we are analyzing if it is indeed preparations for an additional test or if it is just to pressure Seoul and Washington."

Combined with the threat to launch a missile in the coming days, North Korea last week told foreign governments to consider evacuating their embassy personnel by Wednesday, April 10, as their safety would not be guaranteed. Another red-letter day would appear to be April 15, the birthday of Kim Il Sung, the late founder of the nation and a man still revered as "The Great Leader" and "Eternal President."

South Korea and the US have been sufficiently concerned at the renewed threats to ramp up their own defensive steps. While the South Korean Defense Ministry on Monday dismissed the suggestion of an imminent nuclear test, saying satellite images showed normal activity in Punggye-ri, and not increased activity, as had been suggested, it also said there was a possibility the North would test-fire a missile.

Deploying drones

The US military is considering deploying a unit of Global Hawk reconnaissance drones at Misawa Air Base, in northern Japan, the Japanese defense minister confirmed on Saturday, April 6. The minister, Itsunori Onodera, declined to speculate on the missions that the unmanned aircraft would carry out, but they have been used to great effect in Afghanistan to carry out surveillance work and even attack targets.

The Pentagon's top commander in South Korea has cancelled a scheduled trip to Washington this week as the US is at full alert for any new provocative moves from north of the border, US Forces Korea said in a statement.

General James Thurman had been planning to discuss the operations of the 28,500 US troops stationed in South Korea.

"Given the current situation, General Thurman will remain in Seoul ... as a prudent measure," USFK said.

General Jung Seung-jo, the chairman of the South's Joint Chiefs of Staff was also due to travel to Washington for annual talks with his US counterpart on April 16, but that plan has also been cancelled due to the tensions on the Korean peninsula.

Japan ready to fire

In Tokyo, Defense Minister Onodera on Sunday ordered the Self-Defense Forces to be ready to shoot down a North Korean ballistic missile should it approach Japanese air space. Aegis destroyers equipped with advanced interceptor missiles are to be deployed in the Sea of Japan over the next few days, while Patriot Advanced Capability-3 missile systems are to be deployed in Okinawa - a major base for the US military - on a permanent basis from late April.

China is also keeping up the pressure on its former close ally, with the state-run newspaper the Global Times reporting recently that Beijing has put its armed forces on alert and is massing troops and fighter aircraft on its border with North Korea.

The paper reported that "Large groups of soldiers were seen on the streets of Ji'an, a city in Jilin, amid reports that the [army] had been ordered to combat readiness status.

"Heavy armored vehicles, including tanks and armored personnel cariers, were reported moving near the Yalu River that separates China from North Korea," it added.

Yet another potential prong to any attack from the North would involve the shadowy Unit 121.

Defectors from the North have warned that any military action will be accompanied by Unit 121's concerted cyberwarfare attacks as the North seeks to level a military playing field on which it is at a huge disadvantage due to the technological superiority enjoyed by the United States and its ally, South Korea.

3,000 cyberwarriors

Reports suggest that there are as many as 3,000 skilled "cyberwarriors" in Unit 121, which comes under the Reconnaissance General Bureau and is charged with a variety of attacks on foreign computer systems, starting with the Distributed Denial-of-Service attack, which causes a targeted computer to crash by simply overloading it with data.

The sophistication of the North's cyberwarfare teams was demonstrated in mid-March, when the computer networks of three South Korean broadcasters and three banks were paralyzed by a coordinated attack.

Seoul has identified no fewer than 442 sites and organizations that are dedicated to attacking South Korean interests through the Internet, including Uriminzokkiri, the regime's main Internet-based media and propaganda site.

Most recently, Unit 121 is believed to have been tasked with breaking into other computer networks to access information and to spread computer viruses, disrupting other nations' abilities to respond to North Korean military provocations.