Iran said it has almost doubled its stock of enriched uranium in less than a month, as it prepares to resume talks with world powers on curbing its nuclear programme.

Tehran has progressively abandoned its commitments to a 2015 nuclear deal since then US president Donald Trump pulled Washington out in 2018, prompting Washington to impose fresh sanctions in response.

"We have more than 210 kilogrammes of uranium enriched to 20 percent, and we've produced 25 kilos at 60 percent, a level that no country apart from those with nuclear arms are able to produce," said Atomic Energy Organisation of Iran (AEOI) spokesman Behrouz Kamalvandi, quoted late Wednesday by state news agency IRNA.

In September, the International Atomic Energy Agency confirmed that Iran had boosted its stocks of uranium enriched above the percentage allowed in the 2015 deal.

On October 10, AEOI head Mohammad Eslami said his country had produced more than 120 kilos of 20-percent enriched uranium, in theory allowing the manufacture of medical isotopes used mainly in diagnosing certain cancers.

Iran was not meant to enrich uranium above 3.67 percent, well below the 90-percent threshold needed for use in a nuclear weapon.

The 2015 agreement with Britain, China, Russia, France, Germany and the United States, offered Iran some sanctions relief in return for curbs on its nuclear programme.

Nuclear negotiations between Iran and world powers are to resume on November 29. Iran has always insisted its nuclear programme is for peaceful purposes.