Iran's Supreme Leader said on Thursday he favoured a parliamentary vote on its nuclear deal reached with world powers and called for sanctions against Tehran to be lifted completely rather than suspended, state television reported.

President Hassan Rouhani, a pragmatist whose 2013 election paved the way to a diplomatic thaw with the West, and his allies have opposed such a parliamentary vote, arguing this would create legal obligations complicating the deal's implementation.

"Parliament should not be sidelined on the nuclear deal issue ... I am not saying lawmakers should ratify or reject the deal. It is up to them to decide," said Ayatollah Ali Khamenei, who has the final say on all state policy in Iran.

"I have told the president that it is not in our interest to not let our lawmakers review the deal," the top Shi'ite Muslim cleric said in remarks broadcast live on state TV.

Khamenei himself has not publicly endorsed or voiced opposition to the Vienna accord, having only praised the work of the Islamic Republic's negotiating team.

A special committee of parliament, where conservative hardliners close to Khamenei are predominant, have begun reviewing the deal before putting it to a vote. But Rouhani's government has not prepared a bill for parliament to vote on.

The landmark deal, clinched on July 14 between Iran and the United States, Germany, France, Russia, China and Britain, is aimed at curbing Iran's nuclear activities to help ensure they remain peaceful in exchange for a removal of economic sanctions.

U.S. President Barack Obama secured enough Senate votes on Wednesday to see the nuclear deal through Congress -- a vote must be taken by Sept. 17 -- but hardline Republicans vowed to pursue their fight to scuttle it by passing new sanctions.

Khamenei said that without a cancellation of sanctions that have hobbled Iran's economy, the deal would be jeopardised.

"Should the sanctions be suspended, then there would be no deal either. So this issue must be resolved. If they only suspend the sanctions, then we will only suspend our nuclear activities," he said. Iran and the Western powers have appeared to differ since the accord was struck on precisely how and when sanctions are to be dismantled.

"Then we could go on and triple the number of centrifuges to 60,000, keep a 20 percent level of uranium enrichment and also accelerate our research and development (R&D) activities," the Supreme Leader added.

The Vienna agreement puts strict limits in all three sensitive areas of Iran's nuclear programme, seen as crucial to creating confidence that Tehran will not covertly seek to develop atomic bombs from enriched uranium.

Iran has said it wants only peaceful nuclear energy.

Prime Minister Benjamin Netanyahu of Israel, Iran's arch regional enemy, insisted on Thursday most Americans agreed with him over dangers posed by Tehran, even as he lost his battle to persuade Congress to reject the deal once Obama had bagged enough votes to get it upheld.

HOSTILITY TO CONTINUE

Khamenei also criticised the United States' Middle East policy, suggesting that antagonism prevailing between Iran and Washington since the 1979 Islamic Revolution in Tehran will not abate because of the nuclear deal.

"Our officials have been banned from holding talks with Americans except on the nuclear issue. This is because our policies differ with America," he said.

"One of America's regional policies is to fully destroy the forces of resistance and wants to retake full control of Iraq and Syria ... America expects Iran to be part of this framework," Khamenei told a session of the Assembly of Experts which has the power both to dismiss a Supreme Leader and to choose one. "But this will never happen."

By "forces of resistance", Khamenei was alluding to Islamist militant groups such as Hezbollah, a close ally -- like Iran -- of Syrian President Bashar al-Assad in his war with rebels trying to overthrow him.

Rouhani has made it clear in his speeches that he favours greater engagement with the world, seeming open to cooperating with the United States to reduce conflict in the Middle East.

But Khamenei and his hardline loyalists remain deeply suspicious of U.S. intentions. Relations with Washington were severed in 1979 and hostility towards the United States remains a central rallying point of influential hardliners in Tehran.