'We Can Bring Them To Their Knees?'
Mattis said today he believes economic sanctions still have a chance of dissuading the Iranian leadership from pursuing a bomb in the first place, should unpopularity in the streets trump nuclear ambitions.
"But if that doesn't work, we can bring them to their knees?" Sen. Graham asked, apparently referring to American military capabilities.
After a long pause, Mattis replied, "Yes sir. There are a number of means to do that, perhaps even short of open conflict. But certainly that's one of the options I have to have prepared for the President."
Mattis' comments come the same day newly minted Secretary of State John Kerry told ABC News' Martha Raddatz that Iran continues to move closer to developing a nuclear weapons capability.
"Lines have been drawn before and they've been passed," Kerry said. "That's why the president has been so definitive this time. This is a very challenging moment with great risks and stakes for everybody because the region will be far less stable and far more threatened if Iran were to have a nuclear weapon."
For years Iranian leaders have maintained the country's nuclear program is strictly for peaceful energy purposes.
ABC News' Rym Momtaz and The Associated Press contributed to this report.