Support for Iran n-deal to grow after implementation: Obama

US President Barack Obama, in an interview has said that the public will better appreciate the Iran nuclear deal after it takes effect.

"When this agreement is implemented and we've seen centrifuges coming out of facilities like Fordow and Natanz, and we've got inspectors on the ground and it becomes clear that Iran in fact is abiding by this agreement, then attitudes will change," Xinhua cited Obama as saying in an interview with National Public Radio (NPR) on Monday.

"People will recognise that, in fact, whatever parade of horribles was presented in opposition have not come true," Obama continued.

Obama was facing deep skepticism in Congress, which votes next month on whether to disapprove the nuclear deal world powers reached with Iran last month.

Many Republicans as well as some prominent Democrats, including Senator Chuck Schumer and House Representative Eliot Engel, have said they will vote against the deal, according to NPR.

In the interview, Obama also spoke strongly of his critics in Congress, accusing Republicans lawmakers of opposing the deal over politics.

"Unfortunately, a large portion of the Republican party, if not a near unanimous portion of Republican representatives, are going to be opposed to anything that I do," Obama said.

In a speech at the American University last week, Obama warned that blocking the accord by Congress would lead to war in the Middle East.

"Congressional rejection of this deal leaves any U.S. administration that is absolutely committed to preventing Iran from getting a nuclear weapon with one option, another war in the Middle East," Obama said. "The choice we face is ultimately between diplomacy or some form of war."