Obama said he was still absolutely convinced that the political framework agreement is the best option to prevent Iran from getting a nuclear weapon.
However, if the negotiators fail to finalize technical details by June 30 and Iran violates the undertaken commitments, Washington may revise its approach to sanctions.
"What I've always said, though, is that there's the possibility of backsliding," Obama said Saturday, noting that it is still too early to talk on the possible outcomes.
In compliance with the framework agreement, Iran undertakes to halt building new enrichment facilities or heavy water reactors for 15 years, and limit its stockpile of enriched uranium while abiding by enhanced transparency procedures. The number of centrifuges operating in Iran will also be cut by more than two-thirds in ten years.
Under the deal, the United Sates, the European Union and the UN Security Council agreed to lift their nuclear-related sanctions after the International Atomic Energy Agency verifies implementation of the agreements by Tehran.
