Pyongyang had previously said it had completed work on its first spy satellite, but Tokyo said the launch was likely a ballistic missile.
A Japanese Coast Guard official said North Korea had notified Japan of plans to launch a “satellite” that could be a ballistic missile between May 31 and June 11.
North Korea has also conducted a series of missile and weapons tests in recent months, including a new solid-fuel intercontinental ballistic missile (ICBM).
Japanese officials believe the launch will involve a ballistic missile, according to a tweet from the prime minister’s office, which it described as a “ballistic missile.” [Pyongyang] described as a satellite”.
A coast guard spokesman told AFP that Pyongyang had informed the Japanese coast guard that a rocket would be launched between May 31 and June 11, which could affect waters off the Yellow Sea, East China Sea and east of the Philippine island of Luzon.
The Japanese prime minister’s office urged North Korea not to launch and said it would work closely with allies.
“We strongly urge North Korea not to launch,” the prime minister’s office said on Twitter, adding that it would cooperate “with relevant countries such as the US and South Korea”.
It said the Japanese government would do its best to collect and analyze launch information.
North Korea announced in April that it had completed development of its first spy satellite. Earlier this month, North Korean leader Kim Jong Un inspected a military satellite facility and approved a “future action plan”. The launch would use long-range missile technology banned by UN Security Council resolutions.
Analysts say the spy satellite is part of an effort by nuclear-armed North Korea to advance surveillance technology, including drones, and improve its ability to strike targets in the event of conflict.
North Korean media had previously criticized plans by South Korea, the United States and Japan to share real-time data on Pyongyang’s missile launches, saying the three parties were discussing “sinister measures” to strengthen military cooperation.
