"For Congress to add additional sanctions before this diplomatic window could be pursued would undermine our credibility about the goal of these sanctions," White House spokesman Josh Earnest said during a media briefing while President Barack Obama was on a West Coast swing. "We're not sanctioning just for the sake of sanctions and we're not sanctioning the Iranians specifically to punish them. We have these sanctions in place to pressure Iran to consider and pursue a diplomatic option."
Some members of Congress want to impose an additional round of sanctions against the Islamic republic despite a six-month deal reached in Geneva, Switzerland, among Iran, the five permanent members of the U.N. Security Council and Germany, which calls for Iran to halt production of near-weapons grade nuclear fuel in exchange for some relief from economic sanctions amounting to $6 billion to $7 billion. The administration says the six-month window would allow more comprehensive negotiations on preventing Iran from obtaining nuclear weapons.
Obama says the toughest sanctions would not change.
"That diplomatic opportunity has presented itself and we should pursue it," Earnest said.
The spokesman repeated the White House contention that sanctions imposed under Obama crippled Iran's economy and brought about the historic deal reached Sunday.
Earnest said the White House's view is that Congress shouldn't pass additional sanctions because it would undermine the cooperation the United States has enjoyed with its allies and partners and would "complicate" the diplomatic opportunity.
Any differences of opinion from normally reliable White House allies in Congress "are easily reconciled because the goal that everybody has here is the same, which is a diplomatic solution to our differences with Iran with regard to their nuclear program" that yields an agreement to prevent Iran from obtaining a nuclear weapon.
In Tehran, powerful Iranian politician Akbar Hashemi Rafsanjani said he believes Iran can reach a comprehensive nuclear agreement with world powers within a year.
He told the Financial Times he thought little of Israel's threats of a military strike to curb Iran's nuclear program.
"Israel is so small; no small fish can eat big fish," he said.
Israeli Prime Minister Binyamin Netanyahu, who views the Islamic republic's nuclear ambitions as a threat to the Jewish state's existence, has vowed Israel will take military action if it determines Iran is getting close to developing a military nuclear capability.
Rafsanjani, 79, told the Times Sunday's interim six-month deal was the hardest step because it meant surmounting a diplomatic rift with Washington dating from the 1979 Islamic revolution.
"It was breaking the ice. The second stage will be more routine," he said, disputing analysts in Tehran and the West who warn the next phase of talks will be considerably harder.
"Part of it [the difficulty in reaching Sunday's breakthrough] was because talking to the U.S. was a taboo," he told the newspaper.
"That taboo could not be easily broken and nuclear talks could not move ahead without the U.S.," said Rafsanjani, chairman of Iran's policy-making Expediency Discernment Council and a former president who lost to hardliner Mahmoud Ahmadinejad in 2005.
A centrist and pragmatic conservative who long argued against Iran's isolation, Rafsanjani struck an alliance with reformers who helped to catapult Hassan Rouhani to the presidency in June.
He said Iran would not abandon its nuclear program but would bring it in line with the 1968 Non-Proliferation Treaty, which permits peaceful nuclear-power development.
"The limitations set by international laws are acceptable to us. The Non-Proliferation Treaty is acceptable to us. Anything more than that would be considered imposed on us," he said.