TEHRAN, Iran — Iran’s sole operational nuclear power reactor has reached full capacity, a senior official said Saturday.

Iran’s deputy nuclear chief, Mohammad Ahmadian, said the reactor at the Bushehr power plant was brought to its “full capacity of 1,000 megawatts” Friday evening. The reactor went into operation for the first time last year at minimum capacity.

The Islamic Republic built the nuclear power plant in the southern Iranian port city with Russian help. The facility is a cornerstone of Iran’s drive to become a technological leader among Muslim nations, with efforts such as an ambitious space program and long-range missile development. Iran also runs smaller research reactors and is building another power reactor.

The United States and some of its allies believe the Bushehr plant is part of an Iranian attempt to develop nuclear weapons. Iran denies the accusation, saying its nuclear program is for peaceful purposes.

The Bushehr project dates back to 1974, when Iran’s U.S.-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 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. Since then, the project has been beset by problems linked to construction and supply glitches. Under the contract, Bushehr was originally scheduled to come on stream in July 1999 but it was repeatedly postponed over technical glitches and financial disputes.

The reactor finally went into operation last summer operating with minimum capacity to undergo tests before full operation.