"There is no proof that Iran even has decided to make a bomb," he told the Brussels Forum conference, alongside EU foreign policy chief Javier Solana, who on behalf of world powers has led talks to curb Tehran's nuclear ambitions.

Lavrov said the UN nuclear watchdog, the International Atomic Energy Agency (IAEA), was best placed to monitor Iran's activities and establish whether it might try to covertly develop a weapon under the guise of a civilian programme.

Lavrov said that "as long as the IAEA works in Iran," real concerns it may develop a bomb could be allayed.

Uranium enrichment, a process that the IAEA monitors, is used to make fuel for a nuclear reactor, but at highly refined levels it can serve to produce the core of an atomic weapon.

"To change it to the weapon grade uranium, you need to do manipulations which would be immediately known by cameras," Lavrov said.

His comments come after US President Barack Obama issued a video message to Iran, offering to open a new chapter in relations with the Islamic Republic. The two nations have not had diplomatic ties since 1980.

"This is an example of how people should be self critical even at the top," Lavrov noted about the message.

"Iran must be engaged as a constructive part of the solution and not of the problem," he said.

"It's negotiations, it's respect and it's engagement of Iran in all the areas... including security dialogue with Iran on all the issues in the Middle East, Pakistan, Afghanistan, Iraq, Lebanon."

Russia, a member of the United Nations Security Council, has generally resisted a more hard-line approach against Iran taken by former US president George W. Bush and is helping Tehran build a nuclear power station.

Solana said it was vital for Moscow and the West to work together to encourage the Islamic republic to accept an international offer of political and economic incentives in exchange for suspending uranium enrichment.

"Cooperation on Iran is fundamental. We really have to face the problem of Iran in a coordinated fashion. This one of the most important challenges. If we get that, we will get a tremendous amount of work done," he said.

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