Vice President JD Vance said no US funds would be transferred to Iran under the framework agreement to the end the war.
"We're not giving them American money, not a single dollar of American money will go to Iran," Vance said on ABC's "Good Morning America."
Instead, the agreement centres on sanctions relief, he said.
"We'll be releasing the text this week, and what everybody will see is that Iran doesn't get a dime of money unless they perform their obligations, and the money that we're talking about is fundamentally sanctions relief."
If Tehran were to give up its stockpiles of highly enriched uranium or allow verification measures enabling the United States to ensure Iran was not developing a nuclear weapon, sanctions could be lifted, Vance said.
"So this is really about walking down a pathway here where the Iranians will be welcomed into the world economy if they do the right thing," he added.
The deal is due to be signed on Friday in Switzerland.
Vance said the agreement had already been signed digitally on Sunday, but did not specify who had signed on behalf of the United States and Iran. No funds had yet been released, he added.
After weeks of negotiations, the United States and Iran agreed on Sunday to a framework accord, though few details of the agreement have been made public.
Many observers have described the deal as an interim step in a diplomatic process that still faces significant obstacles.
