Washington (CNN) -- Iran is offering to resume talks over the country's nuclear program as soon as possible, according to a letter that the nation's nuclear negotiator sent to the European Union.
"We voice our readiness for dialogue on a spectrum of various issues, which can provide ground for constructive and forward-looking cooperation," Iranian nuclear negotiator Saeed Jalili wrote in a letter to European Union foreign policy chief Catherine Ashton.
CNN obtained a copy of the translated letter as Iran announced new steps in its nuclear program.
The letter was a response to an October letter from Ashton, who is leading contacts between Iran and the so-called "P5 plus one" group of nations, inviting Iran to a new round of talks aimed at forging an agreement to address international concerns over Iran's nuclear program.
Western nations believe Iran is seeking a nuclear weapon, and tensions are high amid speculation that Israel may launch a preemptive strike to set back Iran's nuclear program.
Jalili welcomed Ashton's statement of respect for Iran's right to peaceful nuclear program, saying "by committing to this approach, our talks for cooperation based on step-by-step principles and reciprocity on Iran's nuclear issue could be commenced."
A "constructive and positive attitude towards (the) Islamic Republic of Iran's new initiatives in this round of talks could open (a) positive perspective for our negotiation," Jalili wrote. "Therefore, within this context, I propose to resume our talks in order to take fundamental steps for sustainable cooperation in the earliest possibility, in a mutually agreed venue and time."
It was unclear whether Iran's desire for negotiations was a play for time to continue its nuclear development, or a response to pain the regime feels over tough economic sanctions against Iran, which have disrupted the nation's economy.
In response to the latest European Union sanctions on the energy and banking sectors, Iran is cutting oil exports to six European countries: the Netherlands, Spain, Italy, France, Greece and Portugal, Iran's state-run Press TV reported Wednesday.
U.S. Defense Secretary Leon Panetta said U.S. officials would discuss the letter with members of the P5-plus-one group -- U.N. Security Council permanent members China, France, Russia, the United Kingdom and the United States, plus Germany -- to determine the next steps.
"We have always maintained that it's in our interest to try to resume talks with Iran, assuming that those talks are constructive. ... But in order for that to happen, Iran has to meet its international obligations, it has to join the international community, and it has to engage in a sincere and constructive way to achieve a diplomatic resolution," Panetta said.
In Vienna, French Foreign Minister Alain Juppe called the letter "ambiguous," but said it "constitutes the start of opening up from Iran, which says it is ready to talk about its nuclear program."
The letter was sent Tuesday, the day before Iran flaunted a new generation of centrifuges and mastery of the nuclear fuel cycle. President Mahmoud Ahmadinejad, clad in a white lab coat, was on hand to load domestically made fuel rods into the core of a Tehran reactor.
Officials said the first Iranian nuclear fuel rods, produced by Iranian scientists at the Natanz facility in central Iran, would be used at the Tehran Nuclear Research Center, which Iran says is used primarily for medical purposes.
Also announced was an intent to start production of yellowcake, a chemically treated form of uranium ore used for making enriched uranium.
United Nations sanctions ban Iran from importing yellowcake. Domestic production would further Iran's nuclear self-sufficiency.
In a speech, Ahmadinejad hailed the developments as major scientific advancements for the Islamic republic. He said Iran was willing to share its nuclear knowledge with other nations that subscribe to the watchdog International Atomic Energy Agency (IAEA).
The U.S. State Department, however, dismissed Iran's Wednesday announcements as bluster for a domestic audience.
"We frankly don't see a lot new here. This is not big news," State Department spokeswoman Victoria Nuland said. "In fact, it seems to have been hyped. The Iranians for many months have been putting out calendars of accomplishments and based on their own calendars they are many, many months behind.
A November IAEA report found "credible" information that Tehran has carried out work toward nuclear weapons -- including tests of possible bomb components and the IAEA's governing council has adopted a resolution expressing "deep and increasing concern about the unresolved issues regarding the Iranian nuclear program."
Despite Iran's drift away from the international community, Tehran's leaders have refused to bow down, insisting its nuclear program is intended for civilian energy purposes.
Iran called the November IAEA report a fabrication aimed at bolstering U.S. accusations that Iran is working toward making a bomb.
"We will never ever suspend our enrichment," Ali Asghar Soltanieh, Iran's permanent envoy to the IAEA, said in November.
Juppe said Iran must resolve international concerns that it is seeking a nuclear weapon before any easing of sanctions, and that Iran's sincerity would be tested when IAEA inspectors hold talks in Tehran next week.
"If Iran is really ready to discuss and show its sites and documents, then the conditions will be there to restart negotiations," Juppe said.
CNN's Moni Basu contributed to this report.