* Iran would stop 20 pct enrichment if it gets fuel supply
* Ahmadinejad comments on eve of power plant start-up
* Iran's nuclear chief says low-level enrichment must go on
(Updates with Russian response)
By Ramin Mostafavi
BUSHEHR, Iran, Aug 20 (Reuters) - Iran would stop higher-grade enrichment if it is assured of nuclear fuel supplies for a research reactor, President Mahmoud Ahmadinejad was quoted as saying in a Japanese newspaper on Friday.
Published on the eve of the inauguration of Iran's first nuclear power plant, Ahmadinejad's comments appeared to signal a possible willingness to compromise on a key concern for the West regarding the Islamic Republic's nuclear programme.
Major powers suspect Iran is seeking to develop nuclear weapons, a fear heightened by its move in February to start enriching uranium to a level of 20 percent from abaout 3.5 percent previously, taking it closer to weapons-grade levels.
Iran says its work is for peaceful purposes and it was forced to enrich to higher levels after U.N.-backed talks for a fuel swap deal with the United States, Russia and France stalled last year.
In June, the U.N. Security Council passed a fourth sanctions resolution against Tehran, with Washington and Brussels imposing tougher economic punishment. Like previous sanctions, it called for a halt to Iran's entire enrichment programme.
Ahmadinejad has said talks could resume in September, although Supreme Leader Ayatollah Ali Khamenei said on Wednesday Iran would not talk to the United States unless sanctions and military threats were lifted. [ID:nLDE67H1TQ]
In his interview with Japan's Yomiuri Shimbun newspaper, Ahmadinejad said Iran could halt 20 percent enrichment as part of a deal. Major powers have made it clear they want Iran to halt such work as a pre-condition for a fuel exchange agreement.
"We promise to stop enriching uranium to 20 percent purity if we are ensured fuel supply," Ahmadinejad was quoted as saying in the interview, published in Japanese.
Russia welcomed Ahmadinejad's offer on Friday and called for a meeting as soon as possible to discuss uranium supplies to Iran.
"We believe it's necessary to conduct such a meeting, and the sooner the better," Deputy Foreign Minister Sergei Ryabkov said, according to the Itar-Tass news agency, suggesting Moscow was ready to consider Tehran's offer.
In the interview with Yomiuri Shimbun, Ahmadinejad rejected calls for Iran to halt all enrichment, as called for by the U.N. Security Council.
"We have a right to enrich uranium," he was quoted as saying. "We have never initiated war or wanted nuclear bombs."
That was reiterated by Iran's nuclear chief Ali Akbar Salehi who will oversee the introduction of fuel rods into the country's first nuclear power station at Bushehr on the Gulf coast on Saturday.
Salehi called the idea that Iran would suspend all enrichment "defective logic".
"Enrichment in Iran will continue to produce the fuel needed by Bushehr nuclear power plant and other plants to be built in the future in Iran," he told the official news agency IRNA.
Experts say firing up the $1-billion Bushehr plant will not take Iran any closer to building a nuclear bomb as Russia will supply the enriched uranium for the reactor and take away spent fuel rods which could be used to make weapons-grade plutonium.
Salehi said Iran's main enrichment plant at Natanz, once it was working at full capacity, could produce up to 30 tonnes of enriched uranium, only enough for one Bushehr-sized plant. Iran has said it wants to build up to 20 nuclear power plants.
"With the assumption that we will receive (Bushehr's) fuel for 10 years from the Russians, what are we going to do for the 30 to 50 remaining years?" he asked, adding that Iran was not obliged to buy nuclear fuel from the Russians. (Additional reporting by Chisa Fujioka in Tokyo and Hashem Kalantari in Tehran; Writing by Robin Pomeroy and Jon Hemming editing by Andrew Dobbie)