STOCKHOLM: Most of the world鈥檚 nuclear-armed states continued to modernize their arsenals last year, setting the stage for a new nuclear arms race, researchers warned Monday.
The Stockholm International Peace Research Institute (SIPRI) said nuclear powers including the United States and Russia 鈥� which account for around 90 percent of the world鈥檚 stockpile 鈥� had spent time last year 鈥渦pgrading existing weapons and adding newer versions.鈥�
Since the end of the Cold War, old warheads have generally been dismantled quicker than new ones have been deployed, resulting in a decrease in the overall number of warheads.
But SIPRI warned that the trend was likely to be reversed in the coming years.
鈥淲hat we see now, first of all, is that the number of operational nuclear warheads is beginning to increase,鈥� SIPRI Director Dan Smith told AFP.
This was especially the case with China, which SIPRI said had about 600 nuclear warheads and had added 100 new warheads in 2023 and 2024.
鈥淐hina is increasing its nuclear force steadily,鈥� Smith said, adding that the country could reach 1,000 warheads in seven or eight years.
While that would still be well short of Russian and US arsenals it would make China 鈥渁 much bigger player,鈥� said Smith.
He said the world faced new threats 鈥渁t a particularly dangerous and unstable moment鈥� for geopolitics, adding: 鈥淲e see the warning signs of a new nuclear arms race coming.鈥�

SIPRI counted a total of 12,241 warheads in January 2025, of which 9,614 were in stockpiles for potential use.
The institute noted in its report that both Russia and the United States had 鈥渆xtensive programs under way to modernize and replace their nuclear warheads.鈥�
The United Kingdom was not believed to have increased its number of warheads in 2024, but SIPRI said that given the country鈥檚 2021 decision to raise its limit on the number of warheads from 225 to 260, it was likely to increase in the future.
Similarly, while France鈥檚 arsenal was believed to have remained steady at around 290, 鈥渋ts nuclear modernization program progressed during 2024.鈥�
India and Pakistan both 鈥渃ontinued to develop new types of nuclear weapon delivery systems in 2024.鈥�
India had a 鈥済rowing stockpile鈥� of about 180 nuclear weapons at the start of 2025, the institute said, while Pakistan鈥檚 arsenal remained steady at about 170 warheads.

SIPRI also noted that North Korea鈥檚 nuclear weapons program remained 鈥渃entral to its national security strategy,鈥� estimating that it had around 50 warheads and was believed to possess 鈥渆nough fissile material to reach a total of up to 90 warheads.鈥�
Israel 鈥� which does not acknowledge its nuclear weapons 鈥� is also believed to be modernizing its arsenal, which SIPRI estimated was about 90 warheads at the start of the year.
Smith stressed that the looming nuclear arms race would not just be about 鈥渢he numbers of warheads.鈥�
鈥淚t鈥檚 an arms race which is going to be highly technological,鈥� Smith said.
He added that it would be both in 鈥渙uter space and in cyberspace鈥� as the software directing and guiding nuclear weapons would be an area of competition.
The rapid development of artificial intelligence will also likely begin to play a part, at first as a complement to humans.
鈥淭he next step would be moving toward full automation. That is a step that must never be taken,鈥� Smith said.
鈥淚f our prospects of being free of the danger of nuclear war were to be left in the hands of an artificial intelligence, I think that then we would be close to the doomsday scenarios.鈥�