The Bushehr nuclear plant in Iran will go into operation in mid-September, ISNA news agency quoted on Wednesday the head of Iran's Atomic Energy Organization as saying.
German companies began constructing the plant, which is Iran's first, in 1975 but stopped after a U.S. embargo was imposed on high-technology supplies to Iran following the 1979 Islamic Revolution and the subsequent U.S. Embassy siege in Tehran.
Russia signed a contract with Iran in February 1998 to complete construction.
"There are 3,000 Russian specialists working there [Bushehr], and we hope that it [reactor] will start operating in mid-September," Ali Akbar Salehi said, adding that Iran will need an additional $1.5 billion to finish the plant.
Earlier Russia said the construction of the Bushehr plant would not be affected by the new UN sanctions against the Islamic Republic.
The U.N. Security Council approved on June 9 a new package of economic sanctions against Iran over its nuclear program, including tougher financial controls and an expanded arms embargo.
The sanctions also included an asset and travel freeze on more than three dozen companies and individuals.