The State Department admitted Tuesday that Iran will get about $100 billion in frozen assets under the Iran nuclear agreement, just weeks after Secretary of State John Kerry ridiculed that number as "fictional."

As part of sanctions relief under the nuclear agreement, Iran will have access to assets that the U.S. froze. For weeks now, the press has been reporting that this would be about $100 billion.

But in mid-January, Kerry dismissed that estimate, and said it was closer to $55 billion.

"That is a fictional number. I don't know where it comes from," Kerry said on MSNBC of the $100 billion estimate.

But in recent days, Iran has boasted that it will have access to about $100 billion, which prompted questions from reporters on Tuesday. Despite Kerry's remarks, State spokesman John Kirby admitted Tuesday that the U.S. would be releasing about $100 billion to Iran.

But at the same time, Kirby explained that State is viewing the amount as only $55 billion, because it believes Iran will need to spend the other $45 billion to pay off debts. In the logic of the State Department, that means Iran really isn't getting that additional $45 billion.

"We still believe ... that in actuality, the amount of money which is their money that they would now have access to, is just a little bit more than $50 billion," Kirby said.

"Because the rest of it, nearly half of the entire freed up assets — so this is where the $100 [billion] comes in ... that's the total — but we believe that half of that, so roughly $50 billion, is already tied up in debts to the Chinese, or other international commitments," he added.

Kirby also said State believes Iran has "infrastructure requirements" to pay for, which will also help eat away at the $100 billion it gets.

Reporters pushed back by saying that it makes little sense to say Iran isn't getting $100 billion just because it may have plans to pay back debts with the money. They also questioned the accuracy of the Treasury Department's assessment that Iran will need to spend $45 billion to repay debts and on infrastructure.

But Kirby insisted that in State's view, Iran is only getting $55 billion.

"So while the number total may be that their assets that have been unfrozen ... that is not the number that they will have access to," Kirby said. "They will have access to, as we've said all along, just more than $50 billion."

"It's our assessment ... that much of that is already spoken for, that they'll never get to see it," he said.

Kirby also reiterated that State can't say for sure that any of the money won't be used to fund terrorism. "We've said we can't rule out the fact that some of the money may be used to fund their support for terrorism," he said.