(CNN) - The biggest threats to America's national security come not from Iran or North Korea, but from trans-national non-state actors, Secretary of State Hillary Clinton told CNN's Candy Crowley in an exclusive interview to air Sunday.
"Most of us believe the greater threats are the trans-national non-state networks, primarily the extremists – the fundamentalist Islamic extremists who are connected to al Qaeda in the Arab Peninsula," Clinton said. "Or al Qaeda in Pakistan and Afghanistan."
"They continue to try to increase the sophistication of their capacity," the nation's top diplomat added. "The attacks that they're going to make and the…biggest nightmare that any of us have is that one of these terrorist member organizations within this syndicate of terror will get their hands on a weapon of mass destruction."
In the wide-ranging interview that will air on CNN's "State of the Union with Candy Crowley," Clinton also said Iran's latest behavior is a clear indication the country has nuclear ambitions.
"It's like an old saying that if you see a turtle on a fence post in the middle of the woods, he didn't get there by accident, right? Somebody's put him there. And so you draw conclusions from what you see Iran doing," she said.
Clinton specifically pointed to Iran's rejection late last month of a proposal by the International Atomic Energy Agency calling for the country give up a significant portion of its low-enriched uranium in exchange for fuel for Tehran's research reactor. Iran has maintained its nuclear program is only for peaceful purposes.
The full interview will air Sunday at 9 a.m. ET.