A Swedish arms watchdog says the global number of nuclear warheads dropped last year, though none of the nine nuclear powers showed any signs of giving up their atomic weapons.

The Stockholm International Peace Research Institute said Monday the United States, Russia, Britain, France, China, India, Pakistan, Israel and North Korea, together had about 15,395 nuclear weapons on Jan. 1 this year, down from 15,850 a year earlier.

Of those 4,120 were deployed warheads, meaning warheads placed on missiles or on bases with operational forces.

SIPRI said global nuclear arsenals have been shrinking since their Cold War-peak of nearly 70,000 warheads in the mid-1980s. The institute said despite cuts in Russian and U.S. nuclear forces, "both Russia and the USA have extensive and expensive nuclear modernization programs under way."