Good find. I did a quick search trying to track the story down and found nothing.
I did, however, find a nice UN page describing all the different kinds of nuclear weapons available. It's: Nuclear and Radiological Weapons: What's What?
Interestingly enough, the above page is on the UN website, under the catagory of "United Nations Office of Drug Control and Crime Prevention" I'm not exactly sure WHAT to make of that...
Mark W.