Japan has readied its missile defence systems to shoot down a North Korean rocket if it threatens the country, as the UN chief warned that next month's launch could jeopardise food aid.
"I have ordered officials to prepare to deploy the PAC-3 and Aegis warships," Japan's Defence Minister Naoki Tanaka told reporters, referring to surface-to-air missiles and destroyers carrying missiles.
Nuclear-armed North Korea has announced it will launch a rocket in mid-April to put a satellite into orbit, a move that South Korea, the US and other nations see as a pretext for a long-range missile test banned by the UN.
The move by North Korea's new leadership has set off alarm bells across the region.
The Philippines is calling for help from the US to monitor the rocket, part of which is expected to land off the archipelago.
The preparations by Japan come as world leaders, including US President Barack Obama, prepare to meet in Seoul for a summit officially focused on nuclear terrorism.
The North's atomic programme is expected to be the subject of discussion at the talks on Monday and Tuesday, which are also to be attended by the leaders of China, Japan and Russia.
Leading North Korean newspaper Rodong Sinmun again criticised the upcoming summit as a "burlesque" and part of a South Korean smear campaign.
It said South Korea's rulers hope to use the event to escalate the "nuclear racket" against the North and moves for a war against it.
UN Secretary General Ban Ki-moon, who plans to raise the rocket launch at the Seoul summit, said any launch could discourage international aid donors and worsen North Korea's already dire humanitarian situation.
"Such an act would undermine recent positive diplomatic progress and, in its effect on international donors, would likely worsen the humanitarian situation inside the country," he said in a speech in Singapore.
Japan's surface-to-air interceptors will reportedly be deployed on the southern island chain of Okinawa, over which Tokyo believes the projectile may pass.
In a notice to the UN's International Maritime Organisation, North Korea has said the first stage of the rocket will fall in international waters between China and South Korea.
The second stage is expected to splash down just 190 kilometres east of the northern Philippines.
North Korea insists it has the right to conduct what it calls a peaceful satellite launch.
But Mr Ban, a South Korean, said the rocket flight would be a "clear violation" of UN Security Council resolutions and warned that the North already has a "serious humanitarian crisis" on its hands.
