(CNN) — Iranian President Mahmoud Ahmadinejad is offering to resume talks over his country’s nuclear program as soon as possible, according to a letter he sent to the European Union.

CNN obtained a copy of the letter as Iran announced new steps in its nuclear program.

Iran flaunted a new generation of centrifuges and mastery of the nuclear fuel cycle Wednesday as Ahmadinejad, clad in a white lab coat, was on hand to load domestically made fuel rods into the core of a Tehran reactor.

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 outlining the latest developments Wednesday, Ahmadinejad said Iran was willing to share its nuclear knowledge with other nations that subscribe to the watchdog International Atomic Energy Agency (IAEA).

A November IAEA report found “credible” information that Tehran has carried out work toward nuclear weapons — including tests of possible bomb components.

Subsequent punitive measures against Iran have disrupted its 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, Press TV reported Wednesday.

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.

— CNN’s Moni Basu contributed to this report.