Aug. 8 (Bloomberg) -- Iran resumed uranium conversion activities at its nuclear plant in the central city of Isfahan today in a move that could bring prompt the United Nations Security Council to impose sanctions on the Islamic Republic.

Iran began to feed uranium ore concentrate into the first part of its process line, the International Atomic Energy Agency said in an e-mailed statement. The Vienna-based UN agency said that IAEA seals preventing Iran from completing the uranium enrichment process remain intact.

Iran's decision to resume uranium conversion will probably end negotiations with France, Germany and the U.K. The so-called EU-3 countries offered Iran trade and technology incentives in return for a halt in the nuclear fuel cycle. Iran rejected their latest offer on Aug. 6. The U.S. said the UN Security Council in New York should discuss possible sanctions, if Iran resumed processing.

The Islamic Republic also named Ali Larijani to replace Hassan Rohani as Iran's top nuclear negotiator, according to the official Islamic Republic News Agency. Rohani had led Iran's efforts to craft an agreement with European negotiators.

The U.S.-backed European diplomatic effort to get Iran to step back from the brink of pursuing atomic arms is a test of wills between Europe and new Iranian President Mahmoud Ahmadinejad, who was sworn in as president Aug. 3.

The IAEA will hold an emergency meeting of its board of governors tomorrow in Vienna to discuss Iran's decision to restart its uranium program. Conversion is an initial step in enriching uranium, or boosting the concentration of the U-235 isotope that starts and sustains a nuclear reaction.

To contact the reporter on this story: Jonathan Tirone in Vienna at jtirone@bloomberg.net

Last Updated: August 8, 2005 11:25 EDT