The United States is concerned about ______.

A top Russian official says his country and Iran will soon sign a deal paving the way for deliveries of nuclear fuel to the Iranians. Russian Atomic Energy Agency head Alexanda says the deal will require Iran to return all spent nuclear rods to Russia for storage and processing. He said the agreement is to be signed in Iran in the next three or four months with Russia starting fuel shipment shortly thereafter. The requirement that spent fuel rods be returned to Russia is intended to meet U.S. concerns over the possibility that Iran could divert nuclear materials for use in weaponry.