Iran's first nuclear power plant, Bushehr, is back up and running and reconnected to the grid on January 4, the head of the Atomic Energy Organization of Iran (AEOI) said on Wednesday, after a shutdown lasting more than two months.

The Russian-built 1,000 megawatt (MW) facility, which was connected to Iran's national grid in late 2011, has become a growing safety worry for countries around the Gulf.

It was shut in October 2012 after stray bolts were found under some fuel cells in the reactor vessel, according to a Russian industry source.

Iran said, however, it had unloaded the plants' fuel rods as part of a normal procedure linked to transferring responsibility for the plant from Russian to Iranian engineers.

"The Bushehr nuclear power plant is functioning at 100 per cent capacity and sends electricity to the network. The power station was reconnected to the network on Saturday," AEOI chief Fereydoun Abbasi Davani was quoted by the IRNA news agency as saying.

"We have to ensure safe conditions at the plant, because it has many components and they must be compatible with each other and work together," Abbasi Davani said.

Western governments have imposed wide-ranging sanctions on Iran to force it to stop uranium enrichment, which they fear could help Iran develop atomic weapons.

Abbasi Davani reiterated on Wednesday that Iran's nuclear activities are entirely peaceful. He said uranium enrichment to a purity of 20 per cent was continuing at the Natanz facility in central Iran and at Fordow, south of Tehran, as needed.

Last week Iran's chief nuclear negotiator, Saeed Jalili, said the Islamic Republic had agreed to further talks with world powers over its nuclear activities.

No date or location has been set for the next round of talks, but Jalili said they are expected to take place in January.

Separately, Iranian officials are set to hold further negotiations with representatives of the International Atomic Energy Agency (IAEA) in Tehran next week.

Western diplomats have raised concerns that Iran has been cleansing the Parchin military facility of what they allege are nuclear-related explosive tests there prior to providing access for an IAEA visit.

"If representatives of the agency (IAEA) enter negotiations without prejudice ... and take our rights into account, then of course the following meeting will have a result," Abbasi-Davani said.

He spoke while attending a ceremony marking the assassination of Iranian nuclear scientists in early 2012.

Iranian Intelligence Minister Ali Moslehi said on the sidelines of a cabinet meeting on Wednesday that his ministry had foiled more plots to assassinate Iranian nuclear scientists and that details would soon be made public, IRNA reported. -Reuters