A jubilant Iran has passed a major milestone in its drive to produce nuclear energy as the country's first and only atomic power station, bedevilled by repeated delays, finally began operating at the weekend.
The Russian company that completed the 1970s German-designed plant at Bushehr on Iran's Arabian Gulf coast declared the generating unit was brought up to the "minimum controllable level of power".
A spokesman for Atomstroyexport said: "This means that a nuclear reaction has begun. This is one of the final stages in the physical launch of the reactor."
Nuclear proliferation fears aside, Gulf states are deeply concerned about Bushehr. The plant sits at the junction of three tectonic plates and memories of Japan's recent Fukushima nuclear crisis remain vivid. Bushehr is closer to Kuwait city and Doha than it is to Tehran. Iran insists the reactor is quake proof.
The Islamic republic's highly controversial nuclear programme was Washington's top foreign policy concern last year when there was fevered media speculation that the US or Israel could bomb Iran's atomic facilities.
But the subject vanished from the limelight in recent months, as the Arab spring commanded centre stage.
Now Iran's nuclear ambitions have edged back into the news on several fronts. Tehran on Tuesday signalled it was ready to resume stalled talks with major world powers on its nuclear programme.
With typical bombast, Iranian President Mahmoud Ahmadinejad proclaimed that the nuclear issue could be resolved in a one-hour meeting. His critics say he is keen to deflect attention from a recent power struggle with Iran's supreme leader, Ayatollah Ali Khamenei, which left him battered and bruised.
The European Union said yesterday that Tehran's new talks offer contained nothing to justify another meeting, deepening Western suspicions that Iran's intention is to procrastinate while it enriches enough uranium to build a bomb, an ambition Tehran vehemently denies.
Iran's last meeting in January with the six world powers - the US, Russia, China, France, Britain and Germany - failed when Tehran again ruled out suspending uranium enrichment, as demanded by several UN Security Council resolutions since 2006.
Meanwhile, a UN report due to be released today accuses Iran of using front companies, concealment methods in shipping and opaque financial transactions to circumvent sanctions imposed over Tehran's refusal to suspend uranium enrichment.
The report says sanctions have made it more difficult, costlier and riskier for Iran to acquire items needed for its nuclear and ballistic missile programmes.
But, the study adds, sanctions have not persuaded the Iranian regime to halt uranium enrichment.
The apparent breakthrough at Bushehr is a source of immense pride to the regime in Tehran. It touts the plant as a symbol of Iran's Islamic modernity as well as its resilience, resourcefulness and resistance in the face of international sanctions.
Tehran says the facility will start providing power to the national grid within two months, producing 1,000 megawatts, about 2.5 per cent of Iran's electricity usage.
The US and other Western nations for years urged Russia to abandon the Bushehr project, warning it could help Iran build atomic weapons.
Most nuclear experts, however, regard Bushehr to be of little use to Iran in any alleged drive for weapons. The complex is under strict international supervision and runs on imported fuel from Russia, which will also repatriate the plutonium-laced spent fuel that otherwise could, theoretically, be diverted to a weapons programme.
Iran's use of Russian fuel at Bushehr has also enabled Washington to insist that Tehran can peacefully use nuclear energy without producing its own fuel, an argument that has been central to the near decade-old standoff.
Of far more concern to the international community is Iran's uranium enrichment plant at Natanz which Tehran says is producing low-grade fuel for several planned reactors that have yet to be built. If refined to a much higher level, the fuel could be used for nuclear weapons.
In February, the International Atomic Energy Agency (IAEA) said it had new information on "possible military dimensions" to Iran's nuclear plans.
Tehran insists its uranium enrichment is designed solely to power civilian nuclear plants to generate electricity, both to meet surging domestic demand and save the country's vast oil and gas reserves for lucrative export.
The Bushehr plant dates back to 1974, when Iran's US-backed ruler, Shah Mohammad Reza Pahlavi, contracted the German company Siemens to build the reactor. The company withdrew from the project after the 1979 Islamic Revolution.
In 1992, Iran signed a US$1bn (Dh3.6bn) deal with Russia to complete the project and work began three years later. It was meant to be finished before the new millennium.
Suspicious Iranian officials have blamed Russia for delays in the past, accusing Moscow of being a perfidious ally that has used Bushehr as a political bargaining chip with Washington.
Foreign intelligence experts have also said the control systems at Bushehr were penetrated last year by Stuxnet, the mysterious and malicious computer virus. Iran has accused the US and Israel of being behind the virus, while claiming the damage inflicted was minimal.