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.
CIA head: U.S. intel has 'robust' knowledge of Iran nuclear capabilities
"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.
"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.
But Republicans in Congress -- as well as Israeli Prime Minister Benjamin Netanyahu -- have questioned whether Iran will uphold its end of the deal.
Brennan said he is "confident that our intelligence capabilities are sufficiently robust and that we have a good understanding of what the Iranian nuclear program entails."
His comment came as host Chris Wallace asked about Iranian opposition groups' claims that there is a secret nuclear facility that the West hasn't known about.
"It's not an issue or a question of trusting the Iranians on this," Brennan said, adding that both President Barack Obama and Secretary of State John Kerry are comfortable with U.S. demands on nuclear inspections as part of the deal.
"I think we've gone to school on some of those developments over the last decade or so. We can now have a better plan and opportunity to verify some of the things that they are saying that they're going to do and not do," he said.
Brennan also declined to call Iran an ally when it comes to combating ISIS.
"I wouldn't say that Iran is an ally right now. What I'm saying is that the Iranians are pursuing their interests inside of Iraq, some of which include efforts against ISIL in preventing that phenomenon from growing," he said.
The CIA head said ISIS' presence in Iraq and the broader region is counter to both U.S. and Iran interests and the Iranians are stepping up their engagement.
"The Iranians are now engaged with their Iraqi partners to try to push back these forces of terrorism inside Iraq," he said. "At the same time I think they need to be responsible as far as what they're doing inside Iraq and not further enflaming that situation."