TEHRAN, Iran: Iran began loading fuel into the core of its first nuclear power plant on Tuesday, moving closer to the start up of a facility that the US once hoped to stop over fears of Tehran's nuclear ambitions. Iranian authorities see the completion of the plant, built with the help of Russia, as a show of defiance against UN Security Council sanctions against its nuclear program. “Nearly 160 fuel rods have been placed into the core of the reactor ... which will be the energy production stage and a key stage for its operation,” Mohammad Ahmadian, a senior nuclear official told reporters. At the plant's inauguration on Aug. 21, Vice President Ali Akbar Salehi had said loading the fuel into the reactor core would take place in the next two weeks and the plant would then produce electricity by November. A leak in a storage pool delayed the process for months, however, and Iran now says the 1,000-megawatt nuclear plant will begin generating electricity in early 2011. Originally there had been international speculation that the delay was caused by a computer worm found on the laptops of several plant employees. The US withdrew its opposition to the plant after Russia satisfied concerns over how it would be fueled and the fate of the spent fuel rods. Under a deal signed in 2005, Russia will provide nuclear fuel to Iran, then take back the spent fuel, a step meant as a safeguard to ensure it cannot be diverted into a weapons program. Iran has also agreed to allow the UN's nuclear agency to monitor Bushehr and the fuel deliveries. Worries remain, however, over Iran's program to enrich uranium for nuclear fuel since the process can also be used to create weapons grade material. The United States claims that the fuel deal with Russia shows Tehran does not need uranium enrichment, but Iran maintains it will build other nuclear power plants and needs its own fuel source. Iran is already producing its own nuclear fuel _ uranium enriched to about 3.5 percent. It also has started a pilot program of enriching uranium to 20 percent, which officials say is needed for a medical research reactor. Weapons grade material has to be enriched to 90 percent. The Bushehr project dates backs to 1974, when Iran's US-backed Shah Mohammed Reza Pahlavi contracted with the German company Siemens to build the reactor. The company withdrew from the project after the 1979 Islamic revolution toppled the shah and brought hard-line clerics to power. In 1992, Iran signed a $1 billion deal with Russia to complete the project and work began in 1995. Under the contract, the Bushehr nuclear power plant was originally scheduled to come on stream in July 1999 but the start up has been delayed repeatedly by construction and supply glitches. Moscow has cited technical reasons for the delays, but Iranian officials have sporadically criticized Russia, some calling Moscow an “unreliable partner.” Russians began shipping fuel for the plant in 2007 and carried out a test-run in February 2009. The Bushehr plant overlooks the Arabian Gulf and is visible from several miles (kilometers) away with its cream-colored dome dominating the green landscape. Soldiers maintain a 24-hour watch on roads leading up to the plant, manning anti-aircraft guns and supported by numerous radar stations.