Japan's Coast Guard says it has received notice from North Korea of a plan to launch what it claims is a satellite sometime between November 22 and November 30.
The notice specified areas where a projectile is likely to fall -- southwest of North Korea and the Pacific Ocean east of the Philippines. All of them are outside of Japan's exclusive economic zone.
The Coast Guard is urging vessels to be on the alert for any falling objects.
Under International Maritime Organization guidelines, member states are obliged to disclose in advance any plans for military drills or other activities that could pose a threat to vessels.
North Korea made unsuccessful attempts to launch a military spy satellite in May and August. It said it would try again in October, but it didn't follow through with that plan.
Similar notices were sent ahead of the two earlier launches. The Japan Coast Guard says possible time frames were given, and the launches came early in those windows.