Meanwhile, the White House provided a full text of the "technical understandings" to Congress in its continuing efforts to stop hawkish lawmakers from imposing fresh sanctions against Iran over the next six months, as Iran and the major powers will seek a comprehensive agreement through negotiations.
The understandings were reached on Sunday between Iran and the so-called P5+1 group of the United States, Britain, France, Russia, China and Germany for a Joint Plan of Action in implementing the interim deal they inked on Nov. 24 in Geneva.
Under the understandings, Iran has to take steps next Monday and over the course of six months to meet its commitments, including halting production and starting dilution of near-20-percent enriched uranium.
In addition, Iran has to stop enrichment at half of the installed centrifuges at its Natanz plant and three-quarters of those at the Fordow facility, and the two sites will be subject to "daily" inspection by the International Atomic Energy Agency (IAEA).
The IAEA's inspection of Iran's plutonium reactor at Arak will be increased to at least monthly from the current once every three months or longer.
On the part of the P5+1 and the European Union, they will offer Iran 6-7 billion U.S. dollars in relief from sanctions, with some at hand next Monday, while the last installment of 550 million dollars will not be released until July 20.
"The relief is structured so that the overwhelming majority of the sanctions regime, including the key oil, banking and financial sanctions architecture, remains in place," the summary said.
"Shortly after the Joint Plan of Action takes effect on Jan. 20, the United States will determine with our P5+1 partners our approach to the comprehensive solution," the White House said in the summary.
Carney said the IAEA prefers "certain technical aspects" of the understandings to "remain confidential," but the White House released "a detailed summary" in addition to sending a full copy to Congress in meeting its commitment to offer as much information as possible to the public.
A total of 59 senators have voiced their support for a bill aiming to end Iran's oil exports, just shy of a dozen more needed to override President Barack Obama's threatened veto, as their peers in the House of Representatives voted for a similar bill in late July.
In his meeting with Democratic senators on Wednesday night, Obama made what a senator called "an impassioned plea" for Congress not to take up new sanctions on Iran for now.
The White House has warned that a vote for new sanctions would be a "march toward war," challenging those lawmakers supporting the bill to acknowledge publicly they favor military action against Iran.
Iran has said any new sanctions will scuttle the interim deal, while Israel has threatened time and again to launch unilateral military strikes on Iran's nuclear facilities.