North Korea appeared to have launched a rocket on Sunday, Japan's government said, although it was not immediately clear if it had launched the long-range version that the United States, Japan and South Korea have said would be a disguised missile test.
"A rocket appears to have been launched from North Korea," the prime minister's office said in a statement.
North Korea had said it was sending a satellite into space and gave international agencies notice of a planned trajectory that would take the rocket over Japan, dropping booster stages to the east and west.
The United States, South Korea and Japan have said they would see the launch as a test of the North's long-range Taepodong-2 missile, which is designed to fly as far as Alaska. Washington has said there would be consequences if Pyongyang went ahead with the launch.