The world's nuclear powers have continued to modernise and develop their arsenals amid a slight drop in the number of nuclear warheads, according to a Sweden-based peace research institute.
Global stockpiles of nuclear warheads numbered 13,865 at the beginning of this year, a decrease of 600 compared to early 2018, the Stockholm International Peace Research Institute (SIPRI) reported.
The overall estimate included warheads that were active, in storage or ready to be dismantled.
"What we are reporting is that the overall number of nuclear weapons is in decline but all of the nuclear weapon-possessing states are either modernising or have announced plans to modernise their forces," said SIPRI researcher Shannon Kile.
"It is clear that nuclear weapons remain a central element in their military strategies and national security doctrines," he added, citing that nuclear weapons "have not lost their perceived value for national security."
Nine states are acknowledged to possess nuclear weapons: the United States, Russia, Britain, France, China, India, Pakistan, Israel and North Korea.
About 2,000 nuclear warheads were kept at a high state of readiness, SIPRI said.
The US and Russia, the world's main nuclear powers, accounted for over 90 per cent of global stockpiles.
Both countries have reduced their stockpiles in line with a 2010 bilateral treaty on reducing nuclear arms known as New START. The reductions include obsolete warheads from the Cold War, but the pace of reductions is slowing compared to 10 years ago.
"India and Pakistan have continued to both expand their nuclear arsenals," said Mr.Kile, who heads SIPRI's nuclear disarmament, arms control and non-proliferation program.
The two South Asian rivals have also expanded fissile material production capabilities, and could potentially "significantly expand the size of their nuclear arsenals in the next 10 to 15 years," he added.
India was estimated to have about 130 to 140 nuclear warheads, and Pakistan between 150 and 160, a slight increase on 2018.
North Korea in 2018 continued "to prioritise its nuclear weapon program" even though it announced a moratorium on testing of nuclear weapons and medium- and long-range ballistic missiles, the SIPRI Yearbook said.
Mr.Kile said the moratorium was "a good sign, at least for the time being," but underlined it was not clear how long it will remain in place, and cited the need for the US and North Korea to resume talks.
Australian Associated Press