The United Nations chief urged Iran on Friday to implement Security Council resolutions under which Tehran should curb sensitive nuclear activity, but the Islamic state once again signalled it has no intention of doing so.
Secretary General Ban Ki-moon also said Iran must cooperate fully with the U.N. atomic watchdog, which will send a senior team to Tehran next week to seek explanations for a trove of intelligence suggesting Iran has tried to design atomic bombs.
Iran, which is facing tightening U.S. and European sanctions targeting its vital oil exports, rejects Western accusations that its nuclear programme is ultimately designed to provide it with the means and technologies needed to assemble atom bombs.
I have been urging ... all senior authorities of the Iranian government that the onus is on the Iranian side to prove, to convince, the international community that their nuclear development programme is genuinely for peaceful purposes, Ban told a news conference in Vienna.
He said he was deeply concerned by a report by the International Atomic Energy Agency, a Vienna-based U.N. body, in November that detailed alleged research activities in Iran relevant for the development of nuclear weapons capability.
The Iranian authorities must fully comply with relevant Security Council resolutions, he said, referring to several such U.N. texts issued since 2006.
All these issues should be resolved peacefully through negotiations, through dialogue ... there is no alternative, he added, making clear his opposition to any military action mooted as a last resort by Israel and the United States.
Iran has indicated readiness to address concerns raised by the IAEA, whose team will hold two days of talks in Tehran starting Monday, and also to resume wider negotiations with the major powers for the first time in more than a year.
But it has repeatedly dismissed demands that it curb uranium enrichment, and this defiant message was underlined by the head of the country's atomic energy organisation on Friday.
Fereydoun Abbasi-Davani said in Tehran that Iran was ready to provide nuclear fuel enriched to 20 percent to other countries under the supervision of the IAEA, whose task it is to prevent the spread of nuclear weaponry in the world.
Even though Western experts doubt that Iran has the ability to mass-produce such fuel, his statement was a clear indication that Tehran intends to keep refining uranium, a process that can have both civilian and military purposes.
Iran's enrichment to a fissile concentration of 20 percent, compared with the 3.5 percent normally needed to fuel power plants, has drawn Western condemnation as it takes the country significantly closer to 90 percent weapons grade material.
On Wednesday, Iran announced it had loaded domestically-made uranium fuel rods, enriched to 20 percent, into a research reactor for the first time. It also said that upgraded centrifuges able to enrich uranium faster and more efficiently had gone into production.
Nuclear experts cast doubt on the announced achievements, but Western capitals still expressed concern about Iran's refusal to back down in the long-running dispute, which has the potential to spark a wider Middle East conflict.
Today Iran possesses the necessary technology for the production of nuclear fuel at 20 percent and other countries can buy fuel by entering into an agreement under the supervision of the IAEA, Iranian media quoted Abbasi Davani as saying.
(Additional reporting by Hashem Kalantari in Tehran and Michael George in Dubai; Editing by Mark Heinrich)