The comments by Reza Aqazadeh, vice president and head of Iran's Atomic Energy Organization, came just days before the Vienna-based International Atomic Energy Agency is expected to submit its latest report on Iran's nuclear program to the United Nations Security Council early this week.
"I confirm that our technical efforts are going ahead appropriately," IRNA quoted Aqazadeh as saying. "Improving nuclear technology and the installation and operation of 50,000 centrifuges are our aim."
Iran announced in April that it had begun to operate 3,000 centrifuges - 10 times the previously announced number - but the international community responded to the claim with skepticism. Tehran has said its ultimate goal is to have 50,000 centrifuges running at its underground facility in Natanz.
Later in April, The Associated Press obtained a confidential IAEA document saying that Iran was using 1,300 centrifuges at Natanz to enrich uranium, less than Tehran's official claim, but still significant progress. Aqazadeh did not mention a specific number of centrifuges Sunday.
In the enrichment process, uranium gas is injected into cascades of thousands of centrifuges, which spin and purify it. If enriched to a low level, the result is fuel for a nuclear reactor. To a much higher level it can build the material for a nuclear warhead.
The U.S. and some of its allies have accused Iran of secretly developing nuclear weapons and have demanded the country suspend its enrichment activities prior to any negotiations.
Iran has maintained that its program is peaceful and has said it will not stop enrichment despite two sets of UN sanctions and the threat of more. The UN Security Council has set deadline of late May for Iran to suspend enrichment or face additional sanctions.
Both Aqazadeh and Foreign Ministry spokesman Mohammad Ali Hosseini reiterated on Sunday that Iran would not halt enrichment as a precondition to negotiations.
"We do continue this trend [enrichment] and we will not stop it," said Hosseini at his weekly press briefing.
Hosseini also confirmed Sunday that Iran's top nuclear negotiator, Ali Larijani, had agreed to meet European Union foreign policy chief Javier Solana on May 31 to discuss the deadlock over Tehran's nuclear program.
Solana last held talks in April with Larijani, who said at the time they had come closer to a united view on how to break the stalemate.