WASHINGTON (Reuters) - The six world powers negotiating with Iran over its nuclear program would consider limited pullback of sanctions in exchange for clear evidence that Tehran is taking steps to halt the advance of its nuclear program, the White House said on Thursday.
In exchange for "concrete, verifiable measures" to address long-standing international concerns, the six powers "would consider limited, targeted, and reversible relief that does not affect our core sanctions architecture," White House spokesman Jay Carney told reporters at a briefing.
The broader sanctions regime would be maintained until there is a "final, comprehensive, verifiable" agreement that resolves international concerns, he said.
If Iran failed to show progress on its nuclear program, the modest sanctions relief could be reversed, and stiffer sanctions could be imposed, Carney said.
The six world powers are pushing for a step-by-step approach that starts by preventing Iran's nuclear program from moving forward and potentially rolls back parts of it, the White House spokesman said. The Western powers would require greater transparency from Teheran so that the negotiations do not provide cover for Iran to advance its program, he said.
Iran met the United States, Britain, France, Germany, Russia, and China for the first day in scheduled two-day talks in Geneva on Thursday.
(Reporting By Mark Felsenthal and Roberta Rampton; Editing by Sandra Maler)