"We cannot wait longer for a decision by the Iranian side," Vladimir Pavlov, director for Russian contractor Atomstroiexport's Bushehr work, was quoted as saying. "Delays in restarting the financing will bring irreversible consequences."

Pavlov said, however, that negotiations in Tehran between Atomstroiexport and Iranian officials were proving "fairly constructive," RIA Novosti reported.

Russian-Iranian negotiations restarted in Tehran on Monday after talks in Moscow last week failed to break the deadlock.

On Monday, Atomstroiexport announced that the crucial delivery of nuclear fuel to the almost completed facility would be delayed, probably by two months.

Russia accuses Iran of falling behind on payments for work at what is set to be the country's first nuclear power station. Iran claims that Russian financial problems are causing the trouble.

The delays appear to be taking their toll on the ground with Atomstroiexport workers at Bushehr beginning to quit the project, a spokesman for Russia's nuclear power agency Rosatom told AFP on Tuesday.

"These people see that there is a problem with the financing of the project and then they resign. However, Atomstroiextort is continuing construction," he said.

Over 2,000 specialists are currently working on the Bushehr project, he said.

Iran's top nuclear negotiator Ali Larijani on Tuesday voiced anger at the delay, adding that the latest hitch showed the need for Tehran to produce its own fuel.

"It is deplorable that there has been a delay in launching the Bushehr plant," he was quoted as saying by the ISNA news agency. "The Russians should keep their promises on time."

The United States accuses Tehran of hiding a secret military programme and has urged Moscow to back away from construction of Bushehr, which Iran says is needed to generate electricity.

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