Three of the world's nuclear powers -- China, India and Pakistan -- have increased their arsenals over the past year, while the other five have cut their strength or kept it stable, the Stockholm International Peace Research Institute said Monday.
China now has 250 nuclear warheads against 240 in 2012, while 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.
According to SIPRI, the arms race is all the more disturbing because of what the institute called a "fragile" peace in Asia, characterised by growing tensions since 2008 between India and Pakistan, China and Japan, and the two Koreas, among 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.
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.
"Once again there was little to inspire hope that the nuclear weapon-possessing states are genuinely willing to give up their nuclear arsenals. The long-term modernisation programmes under way in these states suggest that nuclear weapons are still a marker of international status and power," said SIPRI Senior Researcher Shannon Kile.
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.
The United States and Russia have not destroyed all their chemical weapons in 2012 as promised, and Syria has said it is prepared to use them in the case of foreign attack.
SIPRI figures also show that the number of peacekeepers deployed around the world fell by more than 10 percent in 2012, reflecting partly the beginning withdrawal of international forces from Afghanistan.
SIPRI noted an increase in recent years in the number of intrastate conflicts that are internationalised, as outside states have supported one side or another.
"Such involvement often has the effect of increasing casualty rates and prolonging conflicts," SIPRI said in its report.
SIPRI's annual report also contains data already published, including figures showing a decline in global arms spending in 2012 of 0.5 percent, the first drop since 1998.
The report also said China has overtaken Britain as the world's fifth largest arms exporter after the United States, Russia, Germany and France.