Russia is set to activate a reactor at Iran's Bushehr nuclear power plant on Aug. 21, Russia's state-run atomic energy corporation Rosatom said Friday.

A Rosatom spokesman said Russia would help load the reactor with fuel, which would be a key step toward starting up the reactor at Iran's first nuclear power plant.

"The fuel will be loaded on Aug. 21," Rosatom spokesman Sergei Novikov was quoted by Itar-Tass news agency as saying.

"This is the start of the physical launch (of the reactor)," he said.

Rosatom director Sergei Kiriyenko and head of the Atomic Energy Organization of Iran Ali Akbar Salehi would be at the launching ceremony, Interfax news agency reported.

Bushehr is located in one of Iran's hottest districts on the Persian Gulf coast. The plant construction started in the 1970s by several German companies, who pulled out following a U.S. embargo on high-tech supplies to Iran after the 1979 Islamic Revolution.

Russia signed a contract with Iran to complete the plant construction in 1998.

The start-up date has been postponed a number of times. It was originally scheduled for September 2007 but was delayed by serious financing shortage.

The Interfax reported that fuel for the first reactor was delivered in January 2008. It is in storage under the seal of the International Atomic Energy Agency. Spent fuel from the reactor will be shipped back to Russia.

Russia has been helping Iran build the plant since the mid-1990s. Russian Prime Minister Vladimir Putin had promised Russia would start up the reactor at the Bushehr plant this summer.