North Korea has threatened retaliation and "merciless punishment" against any country that shoots down the long-range rocket it is preparing to launch this coming week.
By Danielle Demetriou in Tokyo
7:50PM BST 07 Apr 2012
Japan and South Korea have put their armed forces on standby in response to North Korea's plans, prepared to shoot down the missile if it passes over their territory.
North Korea was this weekend believed to be at the first stage of launching the rocket, expected between April 12 and 16, claiming that it is part of the centenary celebrations for the birth of the state's founder Kim Il Sung.
However, the United States, Japan and South Korea believe that in reality it will be a ballistic missile test in violation of UN resolutions.
It is against such a backdrop of rising regional tensions surrounding the Korean peninsula that David Cameron, the Prime Minister, will arrive in Japan on a two-day visit this week.
His arrival may, by good fortune, coincide with the blooming of the capital's cherry blossoms, but flower appreciation will take a back seat to regional security issues.
During his visit to Japan on Tuesday and Wednesday, Mr Cameron is expected to meet with both the Emperor at the Imperial Palace as well as his counterpart the prime minister Yoshihiko Noda.
One issue that is expected to top the agenda at his meeting with Mr Noda is a discussion about joint development of defence equipment between Japan and the UK, an opportunity for British business after Japan liberised its weapon export laws
The discussions, which will potentially help bolster Japan's military presence in the region, will be timely: it is among a number of Asian nations currently reinforcing its security in response to both a major military build-up of China and instability in North Korea.
The issue is likely to top the agenda this weekend as the foreign ministers from Japan, China and South Korea meet for annual tri-lateral discussions in the eastern Chinese city of Ningbo.
As well as calling on Pyongyang to show restraint over the coming week, Japan and South Korea are likely to urge China – a key benefactor of the renegade North Korean state – to coordinate closely in response with them to the launch.
Meanwhile, satellite images have shown how North Korea's preparations for its rocket launch are already under way, complete with a mobile radar trailer and rows of apparently empty fuel and oxidiser tanks.
In Japan, hundreds of Self-Defence Force personnel have been dispatched to southern Ishigaki in the Okinawa region, which the second stage of the rocket is expected to fly over.
Japan has deployed missile interceptors to seven locations in Okinawa and the Tokyo region, following orders from Naoki Tanaka, Japan's defence minister, to intercept the rocket if necessary to prevent it from falling onto Japanese soil.
Behind the expected appreciation of the cherry blossoms, the green tea and the polite bows for the cameras during Mr Cameron's visit to Japan this week, the North Korea issue is one that will loom constantly in the background. Video at link