Ayatollah Ali Khamenei
Ayatollah Ali KhameneiReuters

Iran's Supreme Leader, Ayatollah Ali Khamenei, on Tuesday ruled out freezing sensitive nuclear work in the country for a lengthy time period, Reuters reported.

Khamenei also reiterated Iran’s demand that sanctions imposed on it be lifted as soon as a final deal with major powers is reached.

"Freezing Iran's Research and Development (R&D) for a long time like 10 or 12 years is not acceptable," he was quoted as having said in a speech broadcast live on local television.

"All financial and economic sanctions imposed by the UN Security Council, the U.S. Congress or the U.S. government should be lifted immediately when we sign a nuclear agreement," Khamenei continued.

Khamenei voiced trust in Iran's negotiating team but, echoing hardline Iranian military commanders, also ruled out international access to Iran's military sites.

"Inspection of our military sites is out of the question and is one of our red lines," he declared, according to Reuters.

Iran and the six powers reached a framework agreement in April but are in disagreement over many remaining issues as they try to reach a final deal by the June 30 deadline.

In fact, two diplomats said last week that the sides are still apart on all main elements of the nuclear deal, describing the draft of a main document as a patchwork of text and dozens of blank spaces because of stubborn disagreement on up to 10 crucial points.

The comments are in line with ones made by a diplomat who had spoken with a Russian news agency and said the talks are “virtually stalled”.

Among the unresolved issues are the pace of easing Western sanctions imposed over the Iranian program and the monitoring and verification measures to ensure Iran could not pursue a clandestine nuclear weapons program.

Iran has categorically deniedreports that it would allow inspectors into its sites as part of a final deal, describing them as mere rumors and as wrong interpretations of the understanding reached in early April.

Iran’s Deputy Chief of Staff recently reiteratedthat the Islamic Republic will not allow any inspection of its military sites, calling the demand to do so “excessive”.

In addition, UN inspectors regularly monitor Iran's declared nuclear facilities, but the International Atomic Energy Agency (IAEA) has complained for years that Iran is not complying with its probe into its past nuclear activities.

And, in a move that potentially will complicate chances for the final deal with the six powers, Iran's parliament passed a bill on Tuesday banning access for IAEA inspectors to its military sites and scientists.