Related: China Calls for More Diplomacy after Iran Starts 20-pct Uranium Enrichment

Head of Iran's Atomic Energy Organization (IAEO) Ali Akbar Salehi said on Tuesday that Iran began to produce 20 percent enriched uranium at the Natanz facility, the official IRNA news agency reported.

"From today, we will start the 20 percent (uranium) enrichment in a separate cascade in Natanz (nuclear enrichment facility)," Salehi was quoted as saying by the IRNA.

Meanwhile, local English-language Press TV reported that Iran on Tuesday began enriching uranium to a level of 20 percent at its Natanz enrichment facility under the surveillance of inspectors from the international nuclear watchdog.

Iranian Foreign Ministry Spokesman Ramin Mehman-Parast said Tuesday that Tehran is still open to talks over a nuclear fuel swap with the West, the Press TV reported.

"The issue of a nuclear fuel swap is still open (to talks). We have announced our conditions in a clear and transparent way. If the other sides satisfy our conditions and adopt a realistic approach, it (the swap) will be possible," the report quoted him as saying.

He added that a fuel swap with Western countries, however, did not require Iran to relinquish other ways of obtaining the fuel.

The fuel swap "by no means goes counter to obtaining the required fuel through other means," Mehman-Parast said.

On Sunday, Iranian President Mahmoud Ahmadinejad ordered the IAEO to start work on enriching uranium to a purity of 20 percent. Ahmadinejad also said that Iran is still ready for exchange of nuclear fuel with world powers.

On Monday, Iran handed over a letter to the International Atomic Energy Agency (IAEA) informing it about the Islamic Republic's plan to produce 20 percent enriched uranium, provoking fresh warnings by France and the United States of new sanctions.