Iran says its Bushehr nuclear power plant will start working in mid-2008.
The US has backed Russian fuel deliveries to Bushehr
The announcement seems to contradict the state-run Russian contractor building the site which gave a start date of the end of the year.
The Iranian announcement came two days after Iran received a second delivery of enriched uranium from the company. The plant is still being built.
Tehran says it will not stop its domestic enrichment programme despite the threat of more UN sanctions.
"The Bushehr nuclear power station will launch at a capacity of 50% next summer," Iranian foreign minister Manouchehr Mottaki was quoted by the Iranian news agency as saying.
BUSHEHR NUCLEAR PLANT
Begun in 1974 with German assistance
Work halts after Iran's 1979 Islamic revolution
Resumed in 1992 with Russian help
13 Dec: Russia and Iran agree to finish plant after numerous delays
Two pressurised water reactors
First to be completed in a year at the earliest
No explanation was forthcoming for the apparent contradiction.
The United States has said it believes Iran is planning to build a nuclear bomb. But Iran has always insisted its programme is for peaceful purposes only.
And earlier this month the US released an intelligence report which suggested Iran had stopped its nuclear weapons programme in 2003.
It was soon after the release of that report that Russia began shipping nuclear fuel to Iran.
Washington says it supports the supply of enriched uranium to Iran as long as Moscow retrieves the fuel.
Enriched uranium is used as fuel in nuclear power stations. When it is more highly enriched, it can be used to make nuclear weapons.