"The president maintains as commander-in-chief and has said specifically that he has not taken that threat off the table," Kerry said on CBS's "Face the Nation.".
Kerry added that Iran is going to have to prove itself with actions in order for the deal to proceed.
"Iran will have to prove that its program is really peaceful," he said. "There's nothing built on trust. We're not sitting here pretending that Iran is going to suddenly turn over a new leaf. We have to prove it."