Iran's Supreme Leader Ayatollah Ali Khamenei
Iran's Supreme Leader Ayatollah Ali KhameneiReuters

Iranian supreme leader Ayatollah Ali Khamenei warned anew Thursday that there could be no nuclear deal with the West if sanctions imposed on Tehran are not lifted.

Khamenei, who has the last say in all matters of policy, also said he believes Iran's parliament (majlis) should make up its own mind about landmark July 14 deal struck with six world powers.

"I believe... that it is not in the interest of the majlis to be sidelined," Khamenei said.

"I have no recommendation for the majlis on how it should examine it; it is up to the representatives of the nation to decide whether to reject or ratify it."

Despite his statement, the Iranian parliament is a purely symbolic body, as the Supreme Leader wields ultimate authority.  

Khamenei's comments, published on his personal website, come as a debate rages in Iran over whether the majlis should ratify or reject the deal.

Most US lawmakers oppose it, but President Barack Obama has enough backers in the Senate to uphold his certain veto of any congressional resolution disapproving it.  

The majlis announced in mid-August the makeup of a 15-member panel largely composed of conservative lawmakers to review the deal.

But the government and the deal's negotiators believe a parliamentary vote is not in the best interest of Iran, arguing that it would transform a voluntary promise made by Tehran into a legal obligation.

Iran's parliament and the US Congress need to vote - in the coming weeks - on the agreement struck in Vienna before it can be implemented.

But formal oversight of the accord rests with Iran's Supreme National Security Council, a powerful committee headed by President Hassan Rouhani, which reports to Khamenei.

Khamenei, who has said in past weeks that the fate of the nuclear deal remains unclear, insisted Thursday that if decades of "sanctions are not lifted, then there will be no deal."

He noted that some "American officials speak very badly" of the agreement, without identifying anyone by name.  

"If the framework of sanctions are to be maintained, then why did we negotiate," he asked.

On Wednesday, US Secretary of State John Kerry said Iran will be required to live up to the agreement in full before its starts benefiting from sanctions relief.

The deal between Iran and Britain, China, France, Germany, Russia and the United States aims to curb Tehran's nuclear drive in exchange for a gradual lifting of sanctions imposed on its economy since 2006.

But critics say it requires Iran to do little more than pause parts of its program for a limited period in exchange for billions of dollars in sanctions relief, much of it will likely end up in the coffers of Islamist terrorist groups sponsored by Tehran.