(Bloomberg) -- The world’s nuclear-armed nations are set to boost their arsenals in the next decade, even as the number of such weapons fell last year, according to a report from the Stockholm International Peace Research Institute, or SIPRI.

“All of the nuclear-armed states are increasing or upgrading their arsenals and most are sharpening nuclear rhetoric and the role nuclear weapons play in their military strategies,” Wilfred Wan, Director of SIPRI’s Weapons of Mass Destruction Programme, said in a statement on Monday.

That development could reverse a decades-long trend of reduced nuclear stockpiles. By the start of 2022, the global inventory of warheads had declined to 12,705, from more than 34,000 at the beginning of this century, according to SIPRI. While the number of usable nukes has stabilized, total stockpiles continued shrinking last year, as Russia and the US dismantled long-retired warheads.

The risk of nuclear conflict got renewed attention following Russia’s invasion of Ukraine in February, with Western intelligence officials warning that the Kremlin might turn to tactical or other limited nuclear weapons if its war in Ukraine continues to struggle. 

Russian Foreign Minister Sergei Lavrov said in April his country is committed to avoiding nuclear war, while Central Intelligence Agency Director William Burns reiterated last month there is no evidence of Russia planning to deploy or potentially use tactical nuclear weapons.

Bilateral Russia–US strategic stability talks have stalled because of the war in Ukraine, and none of the other nuclear-armed states are pursuing arms control negotiations, SIPRI said.

Read More: Military Spending Passes $2 Trillion as Europe Boosts Defenses

The number of warheads in the usable military stockpiles of Russia and the US -- which together have over 90% of all nuclear weapons -- remained relatively stable last year. China, with the third biggest arsenal, is in the middle of a “substantial expansion” of its nuclear weapon arsenal, including the construction of over 300 new missile silos, it added.

The nuclear-armed permanent members of the UN Security Council -- which also include France and the UK -- jointly stated in January that “nuclear war cannot be won and must never be fought,” while also reaffirming they remain committed to non-proliferation, disarmament and arms control agreements.

“Although there were some significant gains in both nuclear arms control and nuclear disarmament in the past year, the risk of nuclear weapons being used seems higher now than at any time since the height of the Cold War,” SIPRI Director Dan Smith said.

©2022 Bloomberg L.P.