Here is a look at the development of Pyongyang's banned nuclear weapons and ballistic missile programmes, for which it has been hit with international sanctions:

- The beginnings -

North Korea starts working in the late 1970s on a version of the Soviet Scud-B missile with a range of around 300 kilometres (around 200 miles), carrying out its 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, Pyongyang declares a moratorium on such tests as ties with the United States improve.

- 2006-2013: Nuclear tests -

It ends the moratorium in 2005, blaming the "hostile" policy of US President George W. Bush's administration, 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 claims North Korea has successfully miniaturised a thermonuclear warhead. In April, it test-fires a submarine-launched ballistic missile.

On August 3, it launches, for the first time, a ballistic missile directly into Japanese-controlled waters. Later that month, it successfully test-fires another SLBM.

There is a fifth nuclear test on September 9.

- 2017: 'Fire and fury' -

Between February and May, Pyongyang launches a series of ballistic missiles that fall into the Sea of Japan -- also known as the East Sea in Korea.

North Korea claims these are exercises to hit US bases in Japan.

In May, Pyongyang says it has tested the "newly developed mid/long-range strategic ballistic rocket, Hwasong-12". It flies 700 kilometres before landing in the Sea of Japan.

Two months later, North Korea announces it successfully tested on July 4 an inter-continental ballistic missile capable of reaching Alaska -- a gift for the "American bastards" announced on US Independence Day.

There is a second successful ICBM test on July 28.

Then-president Donald Trump threatens Pyongyang on August 8 with "fire and fury" over its missile programme.

- 2017: Largest nuclear test yet -

North Korea conducts its sixth and largest nuclear test on September 3, 2017. 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 United Nations adopts an eighth series of sanctions, North Korea fires an intermediate-range missile over Japan.

Just over a month later, 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, Pyongyang launches a new Hwasong-15 ICBM, which it claims could deliver a "super-large heavy warhead" anywhere on the US mainland.

Analysts agree the rocket is capable of reaching the United States but voice scepticism that Pyongyang has mastered the advanced technology needed to allow the rocket to survive re-entry into the Earth's atmosphere.

- 2018: Olympic detente -

In his New Year speech, Kim says the development of North Korea's nuclear force has been completed.

Catalysed by the Winter Olympics in South Korea, a rapid diplomatic thaw begins in February.

On April 21, Pyongyang says nuclear blasts and ICBM launches will cease immediately and the atomic test site at Punggye-ri will be dismantled to "transparently guarantee" the end of testing.

- 2019-2022: New weapons, new tensions -

After the Hanoi summit in February 2019, negotiations between the United States and North Korea are deadlocked.

There are fresh tensions in 2021 with North Korea carrying out a number of high-profile weapons tests, including a claimed submarine-launched ballistic missile, a long-range cruise missile, a train-launched weapon, and what it says is a hypersonic gliding missile.

And in its first major weapons test of 2022, North Korea says it has carried out a second hypersonic missile test, with a warhead capable of gliding as well as lateral movement during flight.

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