Final tests were completed at the Bushehr Nuclear Power Plant in Iran ahead of the scheduled launch in mid-September, Russia's Atomstroyexport said in a statement on Thursday.
"Efficiency tests of the reactor equipment and supporting technological systems was held," Atomstroyexport, the Russian company building the Bushehr facility, said in a statement.
The company also said it had finished the so-called hot operational testing that was the final stage before the launch.
In June, Iran's nuclear chief, Ali Akbar Salehi said Bushehr NPP would go into operation in mid-September.
Earlier, Russia said the construction of the Bushehr plant would not be affected by UN sanctions against the Islamic Republic.
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 the construction.