Japanese Prime Minister Shinzo Abe has said he would do all in his power to protect the Japanese public after a North Korean missile passed over the north of the country.

"We will make utmost efforts to firmly protect the lives of the people," Mr Abe told reporters in brief remarks as he entered his office for emergency meetings on the missile firing.

The Japanese government confirmed that a North Korean ballistic passed over the island of Hokkaido in the early hours of Tuesday morning.

The government's J-Alert warning system advised people in the area to take precautions, but public broadcaster NHK said there was no sign of damage.

The Japanese military did not attempt to shoot down the missile, which passed over Japanese territory at around 6.06am local time (10.06pm Irish time).

NHK has reported that the missile broke into three pieces and landed in the sea off Hokkaido, the northernmost of the main Japanese islands.

Yoshihide Suga, Japan’s chief cabinet secretary, has said the country will take appropriate steps as needed regarding North Korea following the launch.

Mr Suga described the launch as an unprecedented and grave threat which Japan protests in the strongest terms.

South Korea's military reported that an unidentified pro jectile was fired from a region near the North Korean capital, Pyongyang, in an eastern direction into the Sea of Japan.

They said the launch happened at around 5.57am.

It comes as tensions between North Korea and the United States had appeared to ease after weeks of threats.

North Korean leader Kim Jong Un had threatened to fire missiles into the sea near the US Pacific territory of Guam, with USPresident Donald Trump warning Pyongyang would face "fire and fury" if it threatened the United States.