Reuters

Iran's isolation over its nuclear ambitions deepened as Russia, its closest big power ally, announced indefinite delays to a joint nuclear power project and accused Tehran of abusing its goodwill.

Russia has defied Western concerns to supply arms to Iran, help build the Bushehr nuclear power station and water down sanctions against Tehran in the United Nations, but is now signaling that its patience with Iran's leadership is wearing thin.

Atomstroiexport, the state-owned contractor helping to build the Bushehr plant, said the first fuel deliveries would not go ahead as planned this month and that the scheduled September launch date would not be met.

The contractor said the delays were caused by a payment dispute, but observers in Moscow said the project was, in effect, being mothballed because of political sensitivities.

The United States, which suspects Iran of accumulating know-how to build a nuclear bomb, has for years urged Moscow to halt the project, but the Kremlin refused. Iran denies it is seeking a nuclear weapon.

"The time frame has been moved, and so the launch cannot happen in September; we simply cannot do it. If we can't launch the station in September, then we cannot deliver the fuel according to the old timetable either," said Irina Yesipova, a spokeswoman for Atomstroiexport.

That announcement came as Russian news agencies quoted what they called an informed source in Moscow, who accused Tehran of exploiting Russia's diplomatic support while making no concessions in return.

"Unfortunately, the Iranians are abusing our constructive relations and have done nothing to convince our colleagues of the consistency of Tehran's policies," the source was quoted as saying.

There was no indication of the source's identity, but the remarks were reported by all three main news agencies. Senior officials often use them as a back-channel for sending messages to foreign governments.

"We are suffering losses in terms of foreign policy and our image while they stand their ground," the source was quoted as saying.

"If they do not respond to the questions of the [International Atomic Energy Agency], let them answer for themselves."

"They cannot play on our methodical good relations eternally, and they need to understand that."

Russia holds the key to future UN sanctions on Iran because it holds a veto in the UN Security Council and has used its influence to soften previous measures.

The five permanent members of the Council -- the United States, France, Britain, China and Russia -- plus Germany are discussing imposing new sanctions on Iran.

The United States voiced scepticism Monday about Iranian President Mahmoud Ahmadinejad's wish to go before the council to defend Iran's civilian nuclear plans.

"I'm not sure what purpose that would serve," State Department spokesman Tom Casey said.

"The issue here is not explaining Iran's presumed right to civilian nuclear power; the issue here is getting at international-community concerns about Iran's nuclear programs and its pursuit of nuclear weapons," Casey told reporters.

Insiders in Russia's foreign policy establishment say they are convinced that confronting Iran over its nuclear program will not work and that engagement is the best approach.

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