Updated

Iran says it has significantly reduced its stocks of 20 percent-enriched uranium by converting it to reactor fuel.

The announcement appeared aimed at easing Western concerns over Iran's continuing production of 20 percent uranium, which is enriched to a higher level that that used to fuel most energy reactors, closer to the 90 percent needed for a warhead. The U.S. and its allies demand Iran halt all enrichment, which Tehran rejects.

Iran's nuclear chief Ali Akbar Salehi told state TV late Thursday that stocks have fallen from 240 kilograms to around 140 kilograms as it is converted into fuel for a medical research reactor. He said the remainder is also being converted.

An August report by the U.N. nuclear watchdog put Iran's stockpile 20 percent enriched uranium at 185.5 kilograms.