An exterior view shows the Bushehr nuclear power plant near the Persian Gulf, 1,000 kms south of Tehran, Iran, February 26, 2006. Iran has recently announced that it will begin to enrich uranium for its nuclear power program. Others fear that Tehran will not just enrich uranium to the lower level needed for an atomic energy reactor, but to the higher level needed for nuclear weapons. (UPI Photo/Mohammad Kheirkhah)

The shipments began arriving on Dec. 17, and Thursday's delivery brings the total to 66 tons of atomic fuel, the IRNA news agency said. That represents about 80 percent of the total needed to commission the 1,000-megawatt plant.

Two more shipments will complete the agreement, the report said.

However, there is some disagreement between the two countries, the Alalam Satellite TV network reported. Last month, Iranian Foreign Minister Manouchehr Mottaki said the reactor would be working at 50 percent capacity by the middle of the year, but the Russian providers said the deal stipulates a start-up at the end of the year, the broadcaster said.

After the first delivery, Russia said Iran no longer needed to pursue its own uranium enrichment, which is a contentious issue being reviewed by the U.N. Security Council.

There are international concerns the enriched uranium could be used for nuclear warheads, but Tehran repeatedly has said it is solely for electricity generation.