"Nuclear and radioactive materials are still going missing and the information the United Nations atomic agency receives about such incidents may be the tip of the iceberg, said a senior U.N. official."
"Any loss or theft of highly enriched uranium, plutonium or different types of radioactive sources is potentially serious as al Qaeda-style militants could try to use them to make a crude nuclear device or a so-called dirty bomb, experts say.
Khammar Mrabit, a director of the U.N.'s International Atomic Energy Agency (IAEA), said there had been progress in recent years to prevent that from happening. But he said more still needed to be done to enhance nuclear security.
'You have to improve continuously because also on the other side, the bad guys, they are trying to find ways how to evade such detection,' Mrabit said in an interview."