Tehran earlier announced plans to hold tenders for the construction of 19 new nuclear reactors to generate 20 gigawatts of electricity within the next two decades.
"We propose today that you join projects to build Iranian nuclear power plants, but we warn that if you refuse, the Iranian nation will construct nuclear power plants on its own, leaning on its scientists and its opportunities," Mahmoud Ahmadinejad told a rally during a visit to the southern province of Bushehr.
He said that if countries wait another four years before making cooperation proposals, Iran will turn them down.
The Bushehr province is home to Iran's first nuclear power plant, being built by Russian contractor Atomstroyexport. Earlier this week Russia completed the delivery of 82 metric tons of low-enriched uranium to the plant.
Ahmad Fayaz-Bakhsh, deputy head of Iran's Atomic Energy Organization, was quoted by IRNA news agency on Wednesday as saying that the Bushehr plant will be commissioned in October this year.
"The Bushehr project is 93.67% complete. A total of 48,100 tons of the designated 50,000 tons of equipment has been delivered to the site," the representative said.
He said Iran and Russia are currently in talks on nuclear fuel deliveries to Bushehr for the next 10 years.
Fayazbakhsh put the total project cost at $1.2 billion, which he said Iran had paid to Russia in installments.
"The sum has risen by less than 10% since the contract was signed," he said.
The project saw several months of delays last year, which Moscow attributed to payment arrears, but which Iran blamed on pressure from Western nations.
Western nations fear Iran seeks to produce nuclear weapons, but Tehran insists it needs nuclear technology to generate electricity.
Two sets of UN Security Council sanctions are currently in place against Tehran over its refusal to halt uranium enrichment, and a draft on new sanctions is to be considered by the Security Council next month.
