ANKARA (Reuters) - Iran's Supreme Leader Ayatollah Ali Khamenei on Tuesday ruled out freezing sensitive nuclear work in the country for a long time and said sanctions imposed on it should be lifted as soon it reaches a final deal with major powers, state TV reported.
The six - Britain, France, Germany, China, Russia and the United States - want Iran to commit to a verifiable halt of at least 10 years on sensitive nuclear development work as part of a landmark atomic deal they aim to reach by June 30.
They are offering in exchange relief from sanctions that have crippled the oil exporter's economy.
"Freezing Iran's research and development for a long time like 10 or 12 years is not acceptable," Khamenei said in a speech broadcast live.
"All financial and economic sanctions imposed by the U.N. Security Council, the U.S. Congress or the U.S. government should be lifted immediately when we sign a nuclear agreement."
The U.N. International Atomic Energy Agency (IAEA) has been trying to investigate Western allegations that Iran has been working on designing a nuclear warhead. Iran says that its nuclear program is peaceful and that it is working with the IAEA to clear up any suspicions.
Khamenei, who has the final say for Iran on any deal, repeated his stance that Tehran would not give international bodies access to its military sites.
"Inspection of our military sites is out of the question and is one of our red lines," he said.
U.N. inspectors regularly monitor Iran's declared nuclear facilities, but the IAEA has complained for years of a lack of access to sites, equipment, documents and people relevant to its probe.
France and the United States say Iran must step up cooperation with the IAEA if it wants to reach a final deal.
Khamenei accused the United States of wanting to wipe out Iran's nuclear industry.
"America is after destroying our nuclear industry altogether," he said. "Our negotiators' aim is to safeguard Iran's integrity ... and our nuclear achievements during the talks."
Iran reached a tentative deal with the powers on April 2 to allow U.N. inspectors to carry out more intrusive, short-notice inspections under an "Additional Protocol" to the Non-Proliferation Treaty.
(Writing by Parisa Hafezi; Editing by Andrew Roche/Hugh Lawson)