South Korea's Yonhap news agency now says North Korea's launch of a long-range rocket carrying what it says is a satellite may have failed. South Korea's Defence Ministry cannot confirm the report.
The attempted launch defies United Nations sanctions barring it from using ballistic missile technology.
North Korea had notified UN agencies that it planned to launch a rocket carrying an Earth observation satellite, triggering opposition from governments that see it as a long-range missile test.
It initially gave a February 8-25 time frame for the launch but changed that to February 7-14 on Saturday (local time).
The rocket was launched on a southward trajectory, as planned, passing over Japan's southern Okinawa islands, Japan's NHK reported, and appeared to have successfully separated its first stage booster, South Korea's Yonhap reported.
Japanese Prime Minister Shinzo Abe called the launch "absolutely unacceptable".
Last month, North Korea tested a nuclear device for the fourth time, although the United States and other governments have expressed doubt over the North's claim that it exploded a hydrogen bomb.
North Korea is believed to be working on miniaturising a nuclear warhead to mount on a missile, but many experts say it is some time away from perfecting such technology.
It has shown off two versions of a ballistic missile resembling a type that could reach the US West Coast, but there is no evidence the missiles have been tested.
Isolated North Korea says it has a sovereign right to pursue a space program but it is barred under UN Security Council resolutions from using ballistic missile technology.
It last launched a long-range rocket in December 2012, sending into orbit an object it described as a communications satellite.
Reuters / Newshub.