North Korea has ruffled many feathers by a flurry of missile tests in recent weeks, including an intercontinental ballistic missile (ICBM) - one of its most powerful yet. Many countries have criticised the Kim Jong-un regime, already under sanctions, for the tests saying it threatens to destabilise peace in the region. The North's ICBM can reach anywhere in the United States and demonstrates the strengthening of the country's nuclear force, according to military experts. But Mr Kim is determined to expand the North's nuclear arsenal "at the fastest possible speed".
North Korean missiles has the capability to hit target almost anywhere on Earth, a capability it has honed with comprehensive testing.
Here's a look at the expansion of the arsenal and what's in it.
Focus on increasing nuclear warheads: According to New York Times (NYT), North Korea has carried out 34 weapons tests this year, involving ballistic and cruise missiles. On one single day in November, it fired 23 missiles. The outlet further said that the country conducted six nuclear tests between 2006 and 2017 - the last four happened under Mr Kim, who assumed power in 2011. In September 2017, North Korea claimed to have detonated a hydrogen bomb and its explosive power ranged from 50 to 300 kilotons - over 16 times powerful than the bomb dropped on Hiroshima in 1945.
More powerful missiles: Reuters said that in March and November, North Korea sent ballistic missiles soaring more than 6,000 km into space. The high-flying trajectories showed a weapon designed to hit another continent, or even deliver multiple warheads. Pyongyang has also test-fired at least three intermediate-range ballistic missiles (IRBMs) over Japan, including an October 4 flight where the missile - possibly a variant of Hwasong-12 - landed about 3,200 km beyond Japan in the Pacific Ocean.
Short-range missiles not forgotten: Although long-range weapons get more attention, North Korea has been pouring resources into shorter-range systems too, said a Reuters report. Since 2019, Pyongyang has rolled out new and increasingly capable short-range ballistic missiles (SRBMs), many of which can manoeuvre to confound missile defences. Short-range weapons help it prepare for a potential confrontation with its neighbours, especially South Korea, analysts say, which hosts about 28,500 American troops. The North has also tested other advanced weapons, including "hypersonic" missiles, SRBMs for "tactical" nuclear attacks and new submarine launched ballistic missiles (SLBMs).
North Korea has extracted plutonium: The fissile material was extracted from its Soviet-designed nuclear reactor in Yongbyon, said NYT. The process is going ahead full steam and North Korea now has enough fissile material for 40 to 50 nuclear warheads and could produce enough for six or seven bombs a year, according to an estimate by the Arms Control Association.
Testing solid-fuels technology for missiles: More mundane technology such as rocket fuel is also undergoing intense testing in North Korea, said Reuters. Solid fuel - which would allow missiles, including ICBMs - to be launched with little warning, is a particular focus. On December 16, scientists in North Korea tested what they called a "high-thrust" solid-fuel motor that appeared aimed at perfecting a large engine for an ICBM.
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