Deputy national security adviser for strategic communication for President Barack Obama Ben Rhodes said they are now "very close" to a deal with Iran.
"We do believe that we can achieve ... a first step in an agreement that halts the progress of the Iranian nuclear program, rolls back some of elements of that program, in exchange for some modest relief (from sanctions)," Rhodes said in an interview with CNN's "The Lead with Jake Tapper."
The Israeli government is saying too much sanctions relief is being offered, with some Israeli government officials citing it would amount to $20 billion.
"Those estimates from the Israeli government have been much higher than anything we've been contemplating," said Rhodes, who declined to give specific numbers.
"The core sanctions, the oil sanctions, the banking sanctions, will remain in place, even after this first step of an agreement," he added. "Iran will lose more in revenue because of those enforced sanctions, then it would gain from this relief."
"We don't want to do a deal based on trust, we want to do a deal based on verification," the official underlined.
In the deal currently being contemplated, the U.S. is seeking "Iranian action to address their enrichment capacity, their enrichment stockpiles, their plutonium program and reactor in Iraq, and far more intrusive inspections - in exchange for limited relief," Rhodes said.
"We would be able to turn off that relief if Iranians aren't meeting their conditions," said Rhodes. "This is entirely reversible, and so if Iranians aren't meeting our requirements, the deal is off."
"As you're having that negotiation, do you want that program to advance? Or do you want to put the brakes on that program, and roll it back? That's what we're trying to do with this first step agreement," Rhodes said.
"It would be far more destabilizing to allow the Iranians to move forward with their program, as we have negotiations," he added.