Three nuclear-armed countries - China, India and Pakistan - have increased their nuclear arsenals over the past year, the Stockholm International Peace Research Institute said Monday, against the backdrop of what it called a "fragile" peace in Asia.
China now has 250 nuclear warheads against 240 in 2012; Pakistan has increased its warheads by about 10 to between 100 and 120; and India has also added roughly 10 for a total of 90 to 110, SIPRI said in its annual report.
The study said India and Pakistan are also expanding their missile delivery capabilities.
The arms race is all the more disturbing, said SIPRI, because of what the institute called a "fragile" peace in Asia, characterised by growing tensions since 2008 between India and Pakistan, China and Japan, the two Koreas and others.
"While states have avoided direct conflict with each other and have stopped supporting insurgent movements on each other's territory, decades-old suspicions linger and economic integration has not been followed up with political integration," SIPRI said.
Only the two old superpowers have cut their warheads, Russia reducing its number from 10,000 to 8,500, and the United States scaling back from 8,000 to 7,700.
The warheads controlled by France stayed at 300, while Britain's remained at 225 and Israel's at 80.
All five legally recognised nuclear weapon states - China, France, Russia, the UK and the US - are either deploying new nuclear weapon delivery systems or have announced programmes to do so, and appear determined to retain their nuclear arsenals indefinitely, the report said.
Of the five, only China seems to be expanding its nuclear arsenal and SIPRI said and noted that China had overtaken Britain as the world's fifth-largest arms exporter after the US, Russia, Germany and France.
SIPRI acknowledged that the figures were to a large extent estimates, as the nuclear powers aren't equally transparent, China being totally opaque, and Russia gradually becoming less open.
SIPRI does not count North Korea and Iran as nuclear powers yet, as their respective programmes are still considered in their early stages.
While the global total of warheads was down, SIPRI said it did not translate into a significantly diminished nuclear threat.
While the progress towards a global ban on cluster munitions stalled in 2012, it noted the decrease is due mainly to Russia and the US further reducing their inventories of strategic nuclear weapons.
"Once again there was little to inspire hope that the nuclear weapon-possessing states are genuinely willing to give up their nuclear arsenals," said SIPRI Senior Researcher Shannon Kile.
"The long-term modernisation programmes underway in these states suggest that nuclear weapons are still a marker of international status and power."
Efforts to reduce arsenals of chemical and biological weapons have also been slow, according to SIPRI, a long-time advocate of abolishing weapons of mass destruction.