TOKYO: North Korea is unlikely to conduct its planned long-range rocket launch on Thursday because of weather conditions, Japan's Kyodo news agency said, citing a government source.

“The weather is poor, and it is now past the launch time given, so there will probably be no launch,” Kyodo quoted an unnamed government source as saying.

North Korea has said it would launch a rocket carrying a weather satellite sometime between April 12 and 16, between 7 a.m. and noon (2200-0300 GMT), drawing international criticism.

North Korea's five-day window to launch a rocket that has deeply antagonised global opinion opened on Thursday with no immediate signs of takeoff being imminent.

The communist state has said it will launch the rocket between Thursday and Monday, most likely between 2200 GMT and 0300 GMT, to mark Sunday's centenary of the birth of its founding leader Kim Il-Sung.

The rocket will place a satellite in orbit for peaceful research purposes, North Korea says, but Western critics see the launch as a thinly veiled ballistic missile test. The United Nations has banned such tests by Pyongyang.

North Korea says it has installed the satellite payload and fuelled the 30-metre (100-foot) rocket, but officials in South Korea and Japan said there was no sign that liftoff was about to happen on Thursday morning.

A spokesman for South Korea's defence ministry told reporters: “We're closely watching developments.”Japanese Prime Minister Yoshihiko Noda said his country was on full alert, while urging North Korea to show “self-restraint until the last minute.”

“But we want to be fully prepared for any possible contingency,” Noda said, after ordering the deployment of anti-missile batteries on land and at sea to shoot down the rocket if it threatens Japanese territory.

The Japanese government's top spokesman Osamu Fujimura told reporters in Tokyo that he had no fresh information about the planned launch.