US Energy Secretary Ernest Moniz says the highly enriched uranium, from the Dalat Nuclear Research Institute, has gone to Russia where it will be turned into low-enriched reactor fuel.
Moniz did not say when the removal occurred. He also did not specify amounts today.
But other officials at an International Atomic Energy Agency conference on nuclear security said two batches had been removed totaling 16 kilograms (about 35 pounds), with the first shipment taken out six years ago.
The US and Russia have taken the lead in many such operations worldwide.
