Russia vowed to start Iran's nuclear plant in June rejecting U.S. appeal to delay launching until Tehran proves it is not pursuing a nuclear weapons programme.

Prime Minister Vladimir Putin said on Thursday that the Bushehr plant would be launched in June.

The start-up has been repeatedly delayed because of what Moscow described were financial and technical problems.

Later the same day U.S. Secretary of State Hillary Clinton asked Russian Foreign Minister Sergei Lavrov to put off the plant launching. She said it would be “premature to go forward with any project” in the absence of Iranian reassurances on its nuclear ambitions.

Mr. Lavrov responded by saying that the Bushehr nuclear power station would still be launched.

“Bushehr plays a special role in keeping the IAEA [International Atomic Energy Agency] presence in Iran and in securing Iran's compliance with its obligations under the Nuclear Non-Proliferation Treaty,” Mr. Lavrov said.

On the issue of possible new sanctions against Iran the Russian Foreign Minister said there was still “scope for political-diplomatic work” with Iran and that the U.N. Security Council had not yet begun discussing further sanctions against Tehran.

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