Iran began final preparations for the production of 20%-enriched nuclear fuel at the Natanz plant, Reuters said on Tuesday citing an Iranian nuclear official.

"We started preparatory work at 9:30 a.m. [06:00 GMT] in the presence of International Atomic Energy Agency [IAEA] representatives," Reuters quoted Ali Shirzadian, a spokesman for Iran''s Atomic Energy Organization.

The official also said the head of the Iranian nuclear agency, Ali Akbar Salehi, is expected to make a formal announcement later in the day.