Days after world powers and Iran chalked out a framework nuclear agreement, Supreme Leader Ayatollah Ali Khamenei has warned against seeing the preliminary accord as the "guarantee" of a final deal with world powers.
The new deal would require Iran to reduce its uranium enrichment capacity in exchange for relief from economic sanctions. Also, Iran's nuclear facilities will be subject to regular International Atomic Energy Agency (IAEA) inspections, reported the BBC.
The Middle East nation will have to rebuild its heavy-water reactor in Arak so that it cannot produce any more weapons-grade plutonium.
The deal stated clearly that the U.S. and EU sanctions related to Iran's nuclear programme will be lifted in phases, but can be imposed again if Iran failed to abide by the terms of the agreement.
The deal was reached after eight days of negotiations in Lausanne, Switzerland.
The talks between the so-called P5+1 nations- the US, UK, France, China and Russia plus Germany - and Iran continued well beyond the self-imposed deadline of March 31.
The world powers and Iran will now seek to draft a comprehensive nuclear accord by June 30.