In an interview published by Japan's Yomiuri Shimbun newspaper Friday, Ahmadinejad said "We promise to stop enriching uranium to 20 percent purity if we are ensured fuel supply."

An Iranian security guard stands in front of the Bushehr nuclear power plant in southern Iran, Aug. 20, 2010. [Ahmad Halabisaz/Xinhua]

Iran could halt 20 percent enrichment as part of a deal, he was cited as saying in the interview.

Ahmadinejad's comments were apparently aimed at reassuring the United States and other Western countries which have long suspected Iran was seeking to develop nuclear weapons. Tehran denied the charge and insisted its nuclear program was peaceful.

What worries the West most is Iran's refusal to halt uranium enrichment, a process that can be used to make fuel for nuclear weapons.

Adding to the fear is Tehran's move in February to start enriching uranium to 20 percent purity from 3.5 percent, making it closer to weapons-grade level.

Major powers have offered a fuel exchange deal in exchange for Tehran's suspension of its move.

Despite Ahmadinejad's signal, Iran's nuclear chief Saleh said on Friday Iran will continue enriching uranium to make fuel for the Bushehr plant as Tehran may not always buy it from Moscow.

"The Bushehr plant has a lifespan of 60 years and we plan to use it for 40 years. Suppose we will buy fuel (for Bushehr power plant) for 10 years from the Russians, what are we going to do for the rest 30 to 50 years?" Saleh was quoted by state news agency IRNA as saying.

Russia, which has walked a fine line on Iran for years, has welcomed Ahmadinejad's offer and called for a meeting as soon as possible to discuss a fuel replacement scheme for the Iranian research reactor.

"We believe that this meeting should be held as soon as possible. The meeting format is a minor matter, while the agenda of the meeting is an essential issue. We should launch this dialogue as quickly as possible," Russian Deputy Foreign Minister Sergei Ryabkov told Itar-Tass on Friday.

He said Russia would like to invite officials from Turkey and Brazil to participate in this meeting, as these countries signed the Tehran Declaration with Iran on May 17.

Under the deal, Iran agreed to transfer 1,200 kg of low-enriched uranium to Turkey and get within a year 120 kg of 20-percent enriched uranium in return, to keep Tehran's medical research reactor running.