A Russian official said on Thursday that Iran will sign up for a second Russian-built nuclear reactor once the delayed first one, which has already sparked US worries, has been completed. Russia is helping Iran build a nuclear power plant at the Gulf port of Bushehr. Iran says it is for civil use, but the United States has worried it might help the Islamic Republic, which it dubs a "rogue state", develop nuclear weapons. "In principle, he (Iranian President Mohammed Khatami) confirmed that as soon as the equipment for the first reactor leaves the factory, a contract for a second reactor will be signed," Yevgeny Sergeyev, the general director of the Izhorskiye Zavody plant, told journalists.