Washington (CNN) Iran would build a nuclear bomb "at their own peril" if nuclear talks with the United States and other leading countries falter, Central Intelligence Agency Director John Brennan said Sunday.

"I think they realize that there's going to be tremendous costs and consequences and implications if they were to decide to go for a 'breakout,'" Brennan said on "Fox News Sunday," referring to Iran amassing enough of the materials necessary to build a nuclear bomb rather than use those materials for civil energy.

JUST WATCHED Miller: Possible Iran deal risky, but potentially historic Replay More Videos ... MUST WATCH Miller: Possible Iran deal risky, but potentially historic 01:29

"There are a number of things that the United States has available to it to prevent Iran from getting a bomb," Brennan said. "President Obama has made it very clear that we are going to prevent Iran from having that type of nuclear weapon that they may have been going on track to obtain. So if they decide to go down that route they know that they will do so at their own peril."

The United States and several other countries are working quickly to finalize a pact that would thwart Iran's nuclear ambitions, at least temporarily, and in return ease sanctions that the Middle Eastern country has faced in recent years.

Read More