Pyongyang 'fires intermediate range missile' over Japan in new weapons test

South Korea's president Moon Jae-in has instructed his officials to pursue "stern" diplomatic and military measures to discourage North Korea from further provocations after its latest missile launch.

Since President Donald Trump threatened the North with "fire and fury" in August, Pyongyang has conducted its most powerful nuclear test and launched two missiles of increasing range over Japan, an ally of the United States.

The growing frequency, power and confidence displayed by these tests seems to confirm what governments and outside experts have long feared: North Korea is closer than ever to its goal of building a military arsenal that can viably target both US troops in Asia and the US homeland.

This, in turn, is meant to allow North Korea greater military freedom in the region by raising doubts in Seoul and Tokyo that Washington would risk the annihilation of a US city to protect its Asian allies.

North Korea has repeatedly vowed to continue these tests amid what it calls American hostility, by which it means the presence of tens of thousands of American troops in Japan and South Korea.

Robust diplomacy on the issue has been stalled for years, and there is little sign that senior officials from Pyongyang and Washington might sit down to discuss ways to slow the North's determined march toward inclusion among the world's nuclear weapons powers.

The missile was launched from Sunan, Pyongyang's international airport and the origin of the earlier missile that flew over Japan.

Analysts have speculated the new test was of the same intermediate-range missile launched in that earlier flight, the Hwasong-12.

Japanese Prime Minister Shinzo Abe and US Defence Secretary Jim Mattis both called the launch a reckless act.

The UN Security Council scheduled an emergency closed-door meeting to be held on Friday afternoon in New York.

The North American Aerospace Defence Command and the US Pacific Command said the missile posed no threat to North America or to Guam.

North Korea has been accelerating its nuclear weapons development under leader Kim Jong Un, a third-generation dictator who has conducted four of North Korea's six nuclear tests since taking power in 2011.

The weapons are being tested at a torrid pace and include solid-fuel missiles designed to be launched from road mobile launchers or submarines and are thus less detectable beforehand.

North Korea claimed its latest nuclear test was a detonation of a thermonuclear weapon built for its intercontinental ballistic missiles, which could potentially reach deep into the US mainland when perfected.

The UN Security Council unanimously approved new sanctions earlier this week over the nuclear test.

They ban all textile exports and prohibit any country from authorising new work permits for North Korean workers - two key sources of hard currency.

They also prohibit North Korea from importing all natural gas liquids and condensates, and cap Pyongyang's imports of crude oil and refined petroleum products.

AP