(CNN) -- Two days after nuclear talks with world leaders yielded little progress, Iran announced it has opened a new uranium-processing site to mark "National Nuclear Day."
The country opened a uranium-processing facility as well as a uranium mine in the central province of Yazd, state-run TV reported Tuesday.
Iran's enrichment of uranium has been one of the most contentious issues in nuclear talks between Iran and the so-called P5+1 countries -- the United States, France, Britain, China, Russia and Germany.
The P5+1 countries are demanding Iran come clean about its nuclear program, which they suspect includes covert development of nuclear weapons.
But Iran has consistently denied those charges, saying it is enriching uranium and building nuclear reactors only for peaceful civilian energy needs.
"Enrichment is part of the rights of the Iranian people, whether we're talking about 5% or 20%," said Iran's top nuclear negotiator, Saeed Jalili said earlier.
Nuclear power plants use uranium that is enriched to 5%, while making a nuclear bomb requires uranium to be enriched 20% or more, Arnie Gundersen, chief energy adviser with the nuclear consulting group Fairewindes Associates, said last year.
Enriched uranium is the fuel for nuclear power plants that generate electricity.
The technique of enriching uranium relies on yellowcake -- a powdery, often yellow substance that comes from processed, mined uranium ore.
Nuclear talks continue to stall
Despite two days of intense negotiations last week, Iran and six world powers "remain far apart" on Tehran's controversial nuclear program, European Union Foreign Policy Chief Catherine Ashton said Saturday.
Though Jalili described the talks as "substantive, expansive and comprehensive," he said "hostile behaviors" directed toward Iran have been detrimental.
The comment presumably was a reference to the draconian sanctions imposed by Western governments against Tehran, which are crippling the Iranian economy. Oil exports have plummeted over the past several years, as has the value of Iran's currency.
But Ashton defended the use of sanctions.
"The purpose of any sanctions is to put pressure in order to get this process to work," she said. "And I believe we should continue to work as hard as we possibly can to make sure we are successful and we reach a satisfactory resolution."
CNN's Ivan Watson and Reza Sayah contributed to this report.