Obama goes all out to sell Iran n-deal

After reaching what he described as a "historic understanding" with Iran to prevent it from obtaining a nuclear weapon, US President Barack Obama is making an all-out bid to sell the deal at home and abroad.

In calls on Friday to leaders of the Republican-controlled Congress as also allies abroad, Obama and his men stressed that "nothing is agreed until everything is agreed. And if there is backsliding, there will be no deal".

The next three months will be used to finalise the technical details for "a lasting, comprehensive solution that verifiably ensures the peaceful nature of Iran's nuclear programme", he said.

In his weekly address to the American public on Saturday too, Obama stressed he expected a robust debate at home over the framework of a nuclear deal with Iran reached on Thursday.

The deal, he claimed, was "both comprehensive and long term" and "meets our core objectives of cutting off every pathway that Iran could take to develop a nuclear weapon".

He echoed his belief that a diplomatic resolution is by far the best option, and promised to continue to fully brief Congress and the American people on the substance and progress of the negotiations in the months to come.

Obama said there were really three options for dealing with Iran's nuclear programme: bombing Iran's nuclear facilities; abandoning negotiations and hoping for the best with sanctions; or a robust and verifiable deal.

It was his firm belief, Obama said, "that the diplomatic option -- a comprehensive, long-term deal like this -- is by far the best option. For the United States. For our allies. And for the world".

Obama on Thursday night called a sceptical Israeli Prime Minister Benjamin Netanyahu to tell him that the deal represented significant progress toward a solution that prevented Tehran from obtaining a nuclear weapon and emphasised US commitment to Israel.

The Israeli leader, however, insisted that the current framework would threaten the survival of Israel.

He also suggested the deal would legitimise Iran's nuclear programme and not block its path to a bomb, but instead pave its way.

Obama on Friday spoke with King Hamad al Khalifa of Bahrain, Amir Sabah al Sabah of Kuwait, Amir Tamim al Thani of Qatar and Crown Prince Mohammed al Nahyan of the United Arab Emirates to share details of the deal.

He also invited the leaders of the Gulf Cooperation Council to join him at Camp David this spring for further consultations.

Meanwhile, White House spokesperson Josh Earnest told CNN on Friday that "in the last 24 hours, everybody from the President to the White House chief of staff, to officials at the Department of State and the Department of Defence" had reached out to members of Congress to explain the deal.

Obama himself spoke with Republican House Speaker John Boehner and planned to talk to Republican majority and Democratic minority leaders in the House and the Senate.

The Senate Foreign Relations Committee is set to vote on April 14 on a bill put forward by Republican Senator Bob Corker requiring a 60-day congressional review of any nuclear deal.

The White House has emphasised that Congress has the final say on lifting economic sanctions and should play an oversight role.

But White House officials have also warned that Congressional action forcing the US to walk away from the deal would leave Iran in an even stronger position, with very little limiting their nuclear programme.