South Korea and the United States upgraded their coordinated military surveillance status on Wednesday, a report said, ahead of an expected mid-range missile launch by North Korea.

The Combined Forces Command raised the "Watchcon" status from 3 to 2 reflecting indications of a "vital threat", Yonhap said, citing a senior military official.

South Korea's military also launched an emergency task force team to monitor and analyse North Korea's preparations, the official said.

Watchcon 4 is in effect during normal peacetime, while Watchcon 3 reflects indications of an important threat.

Pyongyang is believed to have moved two Musudan missiles to its east coast last week by rail and mounted them on mobile launchers.

Yonhap Tuesday cited South Korean intelligence as saying the North had completed preparations for the expected missile test -- possibly to coincide with April 15 celebrations for the birthday of late founder Kim Il-Sung.

The Korean peninsula has been locked in a cycle of escalating military tensions since the North's third nuclear test in February, which drew toughened UN sanctions.

Pyongyang's bellicose rhetoric has reached fever pitch in recent weeks, with near-daily threats of attacks on US military bases and South Korea in response to ongoing South Korean-US military exercises.

Japan, where the armed forces have been authorised to shoot down any North Korean missile headed towards its territory, said Tuesday it had deployed Patriot missiles in its capital as a pre-emptive defence measure.

A top US military commander said Tuesday that he favoured shooting down a North Korean missile only if it threatened the United States or Washington's allies in the region.

UN chief warns NKorea situation could become 'uncontrollable'
Rome (AFP) April 09, 2013 - UN chief Ban Ki-Moon warned Tuesday that a small incident could provoke an "uncontrollable" situation on the Korean peninsula after North Korea warned of impending "thermo-nuclear" war.

"The current level of tension is very dangerous, a small incident caused by miscalculation or misjudgement may create an uncontrollable situation," Ban said during a visit to Rome.

"I have urged the countries concerned in and around the Korean peninsula to exercise their influence on the North Korean leadership," he said.

"I have spoken to the Chinese leadership and I am going to discuss this with President (Barack) Obama on Thursday," he added.

"The level of tension on the Korean peninsula is not helpful to anybody," he said, adding that all parties should "calm down the tensions and initiate dialogue".

Ban also called on North Korea to re-open the Kaesong industrial complex saying it was "one of the most successful cooperation projects between South and North" and could help build ties.

North Korea said Tuesday the Korean peninsula was headed for "thermo-nuclear" war and advised foreigners in South Korea to consider evacuation -- a warning that was largely greeted with indifference.

It followed a similar warning last week to foreign embassies in its capital Pyongyang to consider evacuating by April 10, with the North saying it could not ensure the safety of their personnel if conflict broke out.