But he said he doesn't believe Iran will be able to use the freed-up cash to boost funding of malign activities if it is serious about revamping its economy.
Kerry said on the sidelines of the World Economic Forum there is little the US or others can do to prevent the now-unfrozen assets from getting into the hands of the Iran Revolutionary Guard Corps or "other entities" that Iran has supported in the past.
"I think that some of it will end up in the hands of the IRGC or other entities, some of which are labeled terrorists," he told CNBC television in an interview.
"You know, to some degree, I'm not going to sit here and tell you that every component of that can be prevented. But I can tell you this: Right now, we are not seeing the early delivery of funds going to that kind of endeavor at this point in time."
Also Read
"If we catch them funding terrorism, they're going to have a problem in the U.S. Congress and other people, obviously," he said.
"Whatever amount may flow to them, I am just trying to be honest, I can't tell people that, 'No, some amount might not,' but we don't believe that that is what has made the difference in the activities of Iran in the region," he said. "It is not money-based, and a whole lot of money isn't going to make a difference in a whole lot of places."
Kerry repeated the Obama administration's argument that many critics of the Iran deal are inflating the amount of money that Iran now has access to. He said estimates of $100 billion to USD 150 billion are incorrect USD 55 billion is more accurate, he said because large chunks of that money is obligated to satisfy foreign debt.