Iran is to insert its first domestically produced high enriched uranium into its Tehran reactor by mid-February, Foreign Minister Ali Akbar Salehi said in comments published by the state IRNA news agency on Thursday.

The announced deadline could sharpen international tensions over Iran's controversial nuclear programme at a time of increased speculation in Israeli and US media of military strikes on Iran's atomic facilities.

"Within the next two months, the first fuel plate produced with the 20% enriched uranium will be placed in Tehran's research reactor," Salehi, who previously headed Iran's nuclear organisation, was quoted as saying.

His statement was an excerpt from a longer interview to be released in full on Saturday, IRNA said.

The West fears Iran's nuclear programme masks a push to develop an atomic weapons capability, a charge Tehran denies.

Four sets of UN sanctions and additional Western measures have been imposed to pressure Iran to halt its enrichment programme before it gets close to producing the 90% level uranium needed for nuclear warheads.

Currently, the Tehran research reactor runs on a stock of 20% enriched fuel imported from Argentina in 1993, but that is nearly depleted.

Iran has been working to enrich its own stock of 3.5% enriched uranium to 20%, which it says it needs for research and medical purposes.

The first batch of 20% enriched uranium was originally to have been ready in September this year, but that date passed with no result.

Western and Israeli news reports last year claimed a computer virus, Stuxnet, had caused Iran's computer-controlled centrifuges used in the process to spin out of control, putting back the programme.

Salehi was quoted by IRNA as saying in mid-October that Iran would produce the 20% enriched uranium by mid-March. His latest comment talking of a mid-February date suggested an acceleration of the process.

The International Atomic Energy Agency in November released its most damning report yet on Iran's nuclear activities, saying it had evidence suggesting research into atomic warheads had been carried out.

Iran rejected the report as "baseless" and biased. (AFP)