North Korean leader Kim Jong Un has declared an end to moratoriums on nuclear and intercontinental ballistic missile tests and threatened a demonstration of a “new strategic weapon”.

Here are the key steps in the development of the regime’s banned nuclear weapons and ballistic missile programmes:

The beginnings, 1970s -

North Korea starts working in the late 1970s on a version of the Soviet Scud-B missile with a range of around 300 kilometres, carrying out a first test in 1984.

Between 1987 and 1992, it begins developing longer-range missiles, including the Taepodong-1 (2,500 km) and Taepodong-2 (6,700 km). The Taepodong-1 is test-fired over Japan in 1998 but the following year,

First nuclear test in 2006 -

It ends the moratorium in 2005, blaming the Bush administration’s “hostile” policy, and carries out its first nuclear test on October 9, 2006.

In May 2009, there is a second underground nuclear test, several times more powerful than the first. Kim Jong Un succeeds his father Kim Jong Il—who dies in December 2011 -- and oversees a third nuclear test in 2013.

2016, Japanese waters reached -

There is a fourth underground nuclear test in January 2016, which Pyongyang claims is a hydrogen bomb.

In March, Kim Jong Un claims the North has successfully miniaturised a thermonuclear warhead, and in April it test-fires a submarine-launched ballistic missile.

On August 3, it fires, for the first time, a ballistic missile directly into Japanese-controlled waters. Later that month, it successfully test-fires another submarine-launched ballistic missile. There is a fifth nuclear test on September 9.

2017, Japan and Guam under threat -

Between February and May, the North tests a series of ballistic missiles that fall into the Sea of Japan. Pyongyang claims these are exercises to hit US bases in Japan.

A test on May 14 is of a “newly developed mid/long-range strategic ballistic rocket, Hwasong-12”, Pyongyang says. It flies 700 kilometres (430 miles) before landing in the Sea of Japan.

Two months later, North Korea announces it successfully tested on July 4 -- the US independence day—an ICBM capable of reaching Alaska, a gift for the “American bastards”. There is a second successful ICBM test on July 28.

Largest nuclear test yet -

On September 3, North Korea conducts its sixth and largest nuclear test. Monitoring groups estimate a yield of 250 kilotons, which is 16 times the size of the 15-kiloton US bomb that destroyed Hiroshima in 1945.

On September 15, less than a week after the UN adopts an eighth series of sanctions, North Korea fires an intermediate-range missile over Japan.

On November 20, Washington declares North Korea a state sponsor of terrorism, a day before adding to pressure on the isolated state with fresh sanctions.

On November 29, North Korea launches a new Hwasong-15 ICBM, which it claims could deliver a “super-large heavy warhead” anywhere on the US mainland.