"The decrease in the overall number of nuclear weapons in the world in 2019 was largely due to the dismantlement of retired nuclear weapons by Russia and the USA — which together still possess over 90 percent of global nuclear weapons", SIPRI said, adding that "despite an overall decrease in the number of nuclear warheads in 2019, all nuclear weapon-possessing states continue to modernize their nuclear arsenals".
SIPRI went on to say that despite the arsenals of other nuclear states being significantly smaller than those of Russia and the US, all of them either began to develop or deploy new nuclear weapon delivery systems or announced their intention to do so.
According to the Institute, China is "in the middle of a significant modernization of its nuclear arsenal", which includes developing a so-called nuclear triad for the first time, made up of new land- and sea-based missiles and nuclear-capable aircraft.
"India and Pakistan are slowly increasing the size and diversity of their nuclear forces, while North Korea continues to prioritize its military nuclear programme as a central element of its national security strategy", the press release read.
As of early 2020, the nine nuclear-armed states — the US, Russia, the United Kingdom, France, China, India, Pakistan, Israel, and North Korea — together possessed an estimated 13,400 nuclear weapons, a decrease from 13,865 the year before, according to the press release.