Russia is the only player able to halt Iran's nuclear programme without the use of force or crippling sanctions, Israel's parliamentary speaker told Russian Foreign Minister Sergei Lavrov on Thursday.

Speaking on a visit to Moscow, Knesset speaker Reuven Rivlin told his host that Russia's close ties with Iran gave it the "opportunity and the obligation" to quash Tehran's nuclear ambitions.

"Russia is the only one able to stop the Iranian nuclear programme without the need for sanctions or military means," said Rivlin, whose comments were released in a statement from his office.

Israel and much of the international community believe Iran's nuclear programme masks a weapons drive, a charge Tehran denies.

The Jewish state, the Middle East's sole, if undeclared, nuclear power, has said a nuclear-armed Iran would pose an existential threat to Israel and it has not ruled out military action of its own to prevent Tehran obtaining such arms.

The Russian foreign ministry confirmed the two men discussed the issue but gave no details of the conversation.

"A number of global and regional problems were discussed, including combating terrorism, the situation around the Iranian nuclear programme and the prospect of creating zones in the Middle East free of weapons of mass destruction," it said in a statement.

Rivlin's office also quoted him as saying that backing embattled Syrian President Bashar al-Assad in his fight against a nearly 19-month domestic uprising could eventually boomerang against Moscow.

"Support for Assad will bring about a situation where non-conventional weapons will fall into the hands of terrorist organisations, which also threaten Russia," he said.

Russia is a key Syrian ally and major arms supplier to the country and has used its veto power within the UN Security Council to block resolutions condemning the Assad regime's use of force.

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