BISHKEK, Kyrgyzstan — Security forces in the ex-Soviet state of Kyrgyzstan have detained a man who tried to sell nuclear-bomb-grade plutonium on the black market, a senior security official said on Wednesday.

Former Soviet states, including Russia with its huge nuclear arsenal, are under heavy pressure to prevent dangerous atomic material from falling into the hands of extremists after the Soviet collapse left many nuclear facilities under-protected.

Tokon Mamytov, deputy head of the Central Asian republic's National Security Service, said the detained man was a Kyrgyz national. Nuclear experts in Moscow said the material was likely to be of Russian origin.

Investigators were trying to establish the identity of the potential buyer and where the substance, identified as plutonium 239, had come from, Mamytov said.

"That was plutonium, no doubt about it. That is the isotope used to make arms," Mamytov said, adding that the radioactive material was packed in 60 ampoules.

He did not say how much the plutonium weighed but said the haul highlighted an alarming growth of black market trade in nuclear materials.

Dozens of nuclear reactors and storage facilities scattered across Russia and Central Asia are a potential lure for extremists because of their arms-grade nuclear material.

Highly enriched uranium and plutonium — found in spent nuclear fuel — can be used to make a standard nuclear bomb. Spent fuel can also produce a "dirty bomb" that spreads radioactive material through a nonnuclear explosion.

In Kyrgyzstan alone, special services have arrested three Kyrgyz citizens trying to sell 110 grams (3.88 ounces) of highly radioactive and toxic caesium-137 for US$110,000 this year.

Russia's nongovernmental nuclear watchdog, Ecodefense, said the material was likely to be Russian-made because plutonium of that type is not stored in Kyrgyzstan.

"Preventing nuclear theft is a very difficult problem," it said. "Spent nuclear fuel is scattered around Russia's 10 nonmilitary nuclear power stations, where security systems are worse than at military sites."

The watchdog said more than 16,000 tons of spent nuclear fuel were stored in nuclear facilities in Russia alone.

Russia's nuclear authority, RosAtom, was not available for comment.

To keep radioactive material safe, the U.N. atomic agency has suggested building the world's first global nuclear waste dump in Russia where it can be stored long-term.

Source: Reuters