As he campaigns to sell skeptical US lawmakers a nascent deal with Iran to rein in its suspect nuclear program, Kerry insisted "the core sanctions regime does not really get eased."
- US says willing to relieve sanction if Iran takes 'first step'
- Senator: Kerry briefing on Iran was 'fairly anti-Israeli'
- US proposes 6-month freeze for Iran's nuclear program
"Ninety-five percent or more of the current sanctions will remain in place," the top US diplomat told MSNBC in an interview, after talks failed to reach a deal in Geneva at the weekend.
Before the sanctions began to bite, Tehran was earning about $110 billion to $120 billion in annual revenue from oil sales, said Kerry, who is leading the push to rally Congress behind efforts to strike a deal to halt Iran's uranium enrichment.
"That has been knocked down to about 40 to 45 billion now because of the sanctions and that 45 billion is frozen in banks around the world. They can't access it," Kerry insisted.
"All we are talking about doing is a tiny portion of that would be released because you have to do something to make it worthwhile for them to say yes, we are going to lock our program where it is today and actually roll it back."
Negotiators from Iran and the six world powers leading the talks - Britain, China, France, Germany, Russia and the United States - are due to meet again on Thursday and Friday next week in Geneva seeking to nail down a deal which has eluded them for a decade.
After the talks failed to reach an accord at the weekend, Kerry said the world powers were very close and were just grappling over "four or five concepts."
He blamed Iran for walking away, saying that at that moment they "couldn't take" the offer that was on the table and had to return to Tehran for consultations.
Iranian Foreign Minister Mohammed Javad Zarif, whose country has denied allegations it is seeking an atomic weapon, has disputed Kerry's version of events.
Kerry urged Congress in closed-door talks Wednesday not to impose even more sanctions on Iran, saying it would "break faith with those negotiations and actually stop them and break them apart."
And he told MSNBC that he had just spoken Thursday with Israeli Prime Minister Benjamin Netanyahu, as he seeks to soothe Israeli anger over the emerging deal.
- Receive Ynetnews updates
directly to your desktop