Secretary of State Hillary ClintonHillary Diane Rodham ClintonChris Murphy’s profile rises with gun tragedies DNC, RNC step up cyber protections Gun proposal picks up GOP support MORE said she was "outraged" by the attack when it occurred Wednesday, and NATO called it a "flagrant breach" of international law.

Turkish officials have warned that Syria was testing the nation's limits, driving concerns that the attacks could expand to a full-fledged war.

Panetta's comments came during a press conference with Peru Defense Minister Pedro Cateriano. At the event, Panetta also said that Iran was feeling the squeeze of international economic sanctions, as it faced mounting pressure to address global worries about its nuclear development efforts. He added that more could be on the way if Iran insists on proceeding.

"Make no mistake, the international community will continue to impose additional sanctions," if Iran does not respond to international demands, he said.