Kiriyenko, head of the Federal Atomic Energy Agency, said after talks with Iranian officials
that resolving questions about Tehran's nuclear program "is absolutely realistic."
He added that Iran has the right to a peaceful nuclear program, but suggested it must act to assure the world that it is not seeking to develop nuclear weapons.
Moscow has offered to enrich uranium for Iran in Russia, in an attempt to allay Western fears that Tehran could divert enriched uranium for the production of nuclear weapons.
Kiriyenko was quoted by Russian news agencies as saying that he was "satisfied with the way" the negotiations were going.
He also said Russia wants to complete the construction of a nuclear power station at Bushehr, in Iran, as soon as possible. Russia is helping Iran build the plant.
The head of Iran's Atomic Energy Organization, Gholamreza Aqazadeh, said on state television after meeting with Kiriyenko that the talks had focused on finalizing the Bushehr nuclear power plant.
(compiled from agency reports)
THE COMPLETE PICTURE: RFE/RL's complete coverage of controversy surrounding Iran's nuclear program.
An annotated timeline
of Iran's nuclear program.