Defense Minister Gen Nakatani told a press briefing that what was believed to be a Nodong medium-range class ballistic missile flew for around 1,000 kilometers and landed in seas off Oga Peninsula, to the west of Akita Prefecture, in Northern Honshu.
Nakatani said that the missile landed within what Japan describes as its exclusive economic zone in the Sea of Japan and said his agency is currently "analyzing the situation."
The defense minister also said that his agency and the coast guard were currently determining whether any damage had been caused to aircraft vessels in the vicinity.
"The launch is in defiance of clear UN Security Council resolutions and is an extremely problematic act from the standpoint of securing the safety of aircraft and vessels at sea,"the Japanese government was quoted as saying in a statement.
Nakatani ordered the nation's Self-Defense Forces (SDF) to be on high alert following the launch, which is believed to have taken place from an area in the South Hwanghae province which lies to the southwest of the DPRK capital Pyongyang and is the first such kind to have landed in what Japan believes to be its territorial waters.
The spate of recent launches, government officials here have said, have been a show of defiance against UN Security Council resolutions slapped on the DPRK for its ongoing nuclear and ballistic missile technology programs which are banned under the council's resolutions.
The DPRK in addition to a number of missile launches and attempts has also conducted four nuclear test which have also been resolutely condemned by Japan and the UN Security Council.