BBC News, Kyrgyzstan
The Central Asian republic of Kyrgyzstan is battling to stop terrorists from getting hold of deadly radioactive materials.
Authorities are unsure where some radioactive material ended up
With the collapse of the Soviet Union, the centralised control of dangerous materials melted away, and many were simply lost or abandoned.
The cash-strapped republic has no real radioactive inventory and little idea where to look.
The rugged, mountainous country is now struggling to regain control before the materials are scooped up by the likes of al-Qaeda's bomb makers.
Needle in a haystack
The Kyrgyz authorities have confirmed that in the last 12 months, they have secured or disposed of a staggering 1,000 items of known radioactive material, judged to be vulnerable to theft or terrorism, acting with American help.
They still have 500 items left to deal with.
But it is the material which is still missing that presents a greater challenge.
With Islamic extremism on the march in the region, and drugs money pouring through the country from Afghanistan, adding radioactive materials to the mix is a dangerous combination.
"These materials need to be secured," said Carolyn MacKenzie of the UN's nuclear watchdog the IAEA, during a quick tour of the country.
"People are killed or injured each year because large sources of radiation are around the world," she said. "They should not be available for people to use maliciously."
Security is lax on the border of Kyrgyzstan and Kazakhstan
Ms MacKenzie's task is gargantuan. She needs to coax and cajole the Kyrgyz authorities to look for lost radioactive material, so called "orphan sources" - items forgotten or abandoned with little or no documentation.
It is a race to find a needle in 10,000 haystacks.
"The person finding the materials," she said, "[is] typically an illiterate scrap worker."
"They see the precious metals around the radioactive source, and they think... money".
But if they try and open it, "the radiation is so intense it can kill them," she said.
Klara Mamushkina of the Kygyrz health ministry is responsible for radiation monitoring.
The ministry is chronically short of funds, and its equipment is obsolete.
She said she had no idea how many radioactive sources were still unaccounted for, but added: "We do need to search for these sources".
Officials also need to make an inventory, but even that costs money they do not have.
According to Carolyn MacKenzie, the authorities need a plan of action. "We can't search the whole country," she said.
Obvious areas of concern are the nation's borders.
Kuban Noruzbaev, of Kyrgyzstan's Ministry of Ecology and Emergency, said there were "concrete examples" of unaccounted radioactive sources which people tried to illegally import into the country.
"People have sometime tried to sell them or illegally import them into the country to re-sell. Scrap metal passing through our territory is (also) sometimes polluted with radioactivity," he said.
Along the porous border with Kazakhstan, frontier guards are few and far between.
Radiation monitoring of the scores of scrap metal trucks crossing in and out of the country is patchy. The area is a smugglers' paradise.
Villagers along the border claim the corruption that acts as a lubricant for terrorism is rife.
A customs official told me that Afghan heroin, with a street value of up to $250bn, flowed through Kyrgyzstan.
If just a tiny percentage is spent of that is on bribes to policemen and others, he said, "the impact could be huge".
"It gives you enormous influence, and the ability to buy what you want, whether it be drugs, weapons or weapons-grade plutonium."
The largest missing radioactive sources are Radioisotope Thermoelectric Generators (RTGs), which traditionally powered mountain top radio transmitters or remote lighthouses.
If dispersed by a simple explosion, the deadly Strontium 90 inside would take over 200 years to decay.
Such a radioactive bomb might kill few people directly, but it could cause panic, as well as widespread economic damage rendering a target area unusable for years.
An Oslo-based environmental group called the Bellona Foundation estimates that there are more than 1,500 unguarded RTGs in the former Soviet Union.
"They are not that big, and it is easy to carry them with you," said Bellona spokesman Nils Boehmer, adding that they are therefore ideal for a terrorist wanting to build a bomb.
It is a chilling combination - radioactive material which is portable and available.
Thieves would probably succumb to the intense radiation, but a suicide team may be prepared to try.
But at the end of her trip of remote mountain airfields and crumbling factory complexes of Kyrgyzstan, Carolyn MacKenzie was upbeat.
"They realise that they have some problems" she said. "There are sources they have lost, and they want to address that now."
"The good news is they are very anxious to start. My challenge will be to get them the tools quickly enough."