Tokyo:North Korea launched a ballistic missile toward the sea on Thursday days after North Korean leader Kim Jong Un vowed to enhance his nuclear arsenal in more practical and offensive ways.

Japan and South Korea are on high alert and expressed concern over this unexpected missile launch.Japan alerted the residents in Japan's northern island of Hokkaido to take cover.

Japanese authorities later retracted the alert, saying an emergency warning system had made an erroneous prediction the missile would fall near the island.

Prime Minister Fumio Kishida of Japan said his government would hold a National Security Council meeting on the launch.

Japan's defence minister, Yasukazu Hamada, said the missile appeared to have been fired eastward at a high angle. He said the missile did not fall in Japanese territory, and that the defence ministry was analysing the launch for more details.

Japan's coast guard said the projectile had fallen in the sea to the east of North Korea. Hamada said he could not confirm whether the missile flew over Japan's exclusive economic zone.

The launch came days after North Korean leader Kim Jong Un called for strengthening the country's war deterrence in a "more practical and offensive" manner to counter Pyongyang called moves of aggression by the United States.

The missile was fired at 7:23 a.m. (2223 GMT on Wednesday) from near Pyongyang, South Korea's Joint Chiefs of Staff said.

The South Korean military said it was on high alert and coordinating closely with the United States.

North Korea has criticised a recent series of joint military exercises between the U.S. and South Korea as escalating tensions, stepping up its weapons tests in recent months.