NORTH KOREA prepares to test medium-range ballistic missile as it CLOSES BORDER with CHINA; PHILIPPINES prepare for Nuclear Winter in mid-summer

• US satellites have located North Korea's missiles
• They have been pictured fueled and ready for launch
• Fears North Korea will not issue test-fire warning

NORTH Korea has closed its border with China, turning back tourists as nuclear tensions continue to mount.

An official at the Dandong Border Office, who declined to give his name, told media: "Travel agencies are not allowed to take tourist groups to go there, since the North Korean government is now asking foreign people to leave. As far as I know, business people can enter and leave North Korea freely."

The move comes after it was revealed United States spy satellites had found two 'missing' North Korean nuclear-capable missiles.

CNN reported US officials were expecting a launch by North Korea "at any time".

Any such "test" launch would be seen as a further escalation of already high tensions in and around the Korean peninsula.

Things could be made worse if North Korea does not issue a "standard warning" of a missile test firing to commercial aviation and maritime shipping.

"We hope they issue a notification but at this point we don't expect it. We are working on the assumption they won't, "the official said.

US officials have confirmed that satellites have been kept over the suspected launch areas for the past week in order to locate - and monitor - the launch vehicles. Bad weather has made their job harder, they said.

The launchers are said to be about half-way down the North Korean east coast and about 20km inland. Satellite imagery shows the missiles have been fuelled and positioned for launch.

The Pentagon has announced it is ready to respond to any missile aimed at America or its allies.

US and South Korean officials have said that the Pyongyang regime may launch the missile as early as Wednesday.

The commander of US forces in the Pacific sought to reassure Congress that the Pentagon would be able intercept a missile. US satellites and radars in the region will be able to detect and quickly calculate the missiles' trajectory.

This would help determine if the launch was hostile - or a test.

The missiles would be shot down by land or sea based anti-missile weapons if they were to track over South Korea or Japan.

Navy Admiral Samuel J. Locklear said: "We have a credible ability to defend the homeland, to defend Hawaii, to defend Guam, to defend our forward deployed forces, and to defend our allies,'' Locklear told the Senate Armed Services Committee.

The US has never sought to shoot down a North Korean missile, and it's unclear if such a move would escalate the tension that has roiled the region. The Obama administration has moved additional military forces into the Pacific, but has sought to calibrate its response in the matter to avoid fueling the crisis.

A "counter-provocation plan" drawn up by US and South Korean officials calls for their combined military forces to respond proportionally to a North Korean attack, but to avoid any step that could set off an escalation of hostilities.

United Nations Secretary-General Ban Ki-Moon has warned that even a slight miscalculation on the Korean peninsula could spiral into an "uncontrollable situation" as he urged North Korea to tone down its provocative rhetoric and ease the "very dangerous" level of tension.

Earlier, Pyongyang urged all foreign companies and tourists in South Korea to evacuate, saying the two countries are on the verge of nuclear war.

The new threat appeared to be an attempt to keep the region on tenterhooks over its intentions.

Analysts see a direct attack on Seoul as extremely unlikely, and there are no overt signs that North Korea's 1.2 million-man army is readying for war, let alone a nuclear one.

South Korea's military has reported missile movements on North Korea's east coast but nothing pointed toward South Korea.

Still, North Korea's earlier warning that it won't be able to guarantee the safety of foreign diplomats after April 10 has raised fears that it will conduct a missile or nuclear test today, resulting in US retaliation.

The United States and South Korea have raised their defense postures, and so has Japan, which deployed PAC-3 missile interceptors in key locations around Tokyo yesterday as a precaution against possible North Korean ballistic missile tests.

"The situation on the Korean Peninsula is inching close to a thermonuclear war due to the evermore undisguised hostile actions of the United States and the south Korean puppet warmongers and their moves for a war against" the North, said a statement by the North Korean Asia-Pacific Peace Committee, an organization that deals with regional matters.

The statement is similar to past threats that analysts call an attempt to raise anxiety in foreign capitals. Observers say a torrent of North Korean prophecies of doom and efforts to raise war hysteria are partly to boost the image of young and relatively untested leader Kim Jong-un at home, and to show him as a decisive military leader.

Another reason could be to use threats of war to win Pyongyang-friendly policy changes in Seoul and Washington. Last week, North Korea told foreign diplomats in Pyongyang that it will not be able to guarantee their safety as of Wednesday. It is not clear what the significance of that date is.

Tourists continued to arrive in Pyongyang despite the war hysteria.

Australian Mark Fahey of Sydney said he was not concerned about a possible war.

"I knew that when I arrived here it would probably be very different to the way it was being reported in the media," he told The Associated Press at Pyongyang airport. He said his family trusts him to make the right judgment but "my colleagues at work think I am crazy."

Chu Kang Jin, a Pyongyang resident, said everything is calm in the city.

"Everyone, including me, is determined to turn out as one to fight for national reunification ... if the enemies spark a war," he said, in a typically nationalist rhetoric that most North Koreans use while speaking to the media.

In Seoul, South Korean Presidential spokeswoman Kim Haing told reporters that the North Korean warning amounted to "psychological warfare."

"We know that foreigners residing in South Korea as well as our nationals are unfazed," she said.

South Korean President Park Geun-hye, who has sought to re-engage North Korea with dialogue and aid since taking office in February, expressed exasperation with what she called the "endless vicious cycle" of Seoul answering Pyongyang's hostile behavior with compromise, only to get more hostility.

Yesterday North Korea said it was suspending work at the Kaesong industrial park near its border, which is combines South Korean technology and know-how with North Korea's cheap labor. North Korea pulled out more than 50,000 workers from the complex, the only remaining product of economic cooperation between the two countries that started about a decade ago when relations were much warmer.

Other projects from previous eras of cooperation such as reunions of families separated by war and tours to a scenic North Korean mountain stopped in recent years.

Miriam warns Philippines: Prepare for 'nuclear winter

Senator Miriam Defensor Santiago, an expert in international law, warned the country of a "nuclear winter" should the ongoing tensions in the Korean peninsula escalate further.

Santiago said the so-called "nuclear winter" creates "dust clouds absorbing the sunlight, dropping temperatures, and damaging agriculture in wide areas of our country."

Initially, a nuclear weapons blast – with the Philippines a possible victim – will release a "fireball of extremely high temperature, Philippine environment could be degraded for generations." Residual effects include severe damage to health, such as leukemia, congenital defects and mental retardation, she said.

But with nuclear taboos compromised due to countries already thinking of striking back, the Philippines should be ready instead with analysis of laws that it could bring to international courts should it become a victim to the standoff.

"Should armed conflict arise, the Philippines should be ready with analyses of certain laws applicable in armed conflict, notably human rights conventions, the Genocide Convention, international humanitarian law, the principle of neutrality, and environmental law," Santiago said.

She said the shift is now towards risk management.

Philippines a Neutral state

Santiago said countries have to respect the integrity of neutral states like the Philippines.

"North Korea would fall under the duty to justify the use of particularly destructive weapons, if they seriously affect neutral countries like the Philippines. The consequences entailed by unjustified use will be governed by the law of state responsibility," she said.

She also noted the country is protected by the principles of environmental law, such as the 1978 ENMOD Convention or the Convention on the prohibition of military or any other hostile use of environmental modification techniques.

"This convention prohibits the use of weapons which have 'widespread, long-lasting, or severe effects' on the environment."

Combat

She also noted there is no treaty that would provide rules in the use of nuclear weapons in combat. "Present treaties deal only with manufacturing, testing, possession, proliferation, deployment, limitation, and reduction of nuclear arms," she said.

While the UN General Assembly has condemned nuclear arms, there are no resolutions adopted by all members, she stressed.

Nonetheless, she said that a nuclear strike hitting the Philippines constitutes a grave breach of humanitarian law.

"Hence, under international law, North Korea would assume the duty to pay reparations, which can amount to extreme proportions. In addition, use of the atomic bomb may qualify as war crimes and as crimes against humanity, under the Rome Statute of the International Criminal Court," she said.

With reports from ABS-CBN News and News.co.au