Secretary of State Hillary ClintonHillary Diane Rodham ClintonBiden slams Trump over golf gif hitting Clinton Overnight Cybersecurity: Equifax hit by earlier hack | What to know about Kaspersky controversy | Officials review EU-US privacy pact Overnight Tech: Equifax hit by earlier undisclosed hack | Facebook takes heat over Russian ads | Alt-right Twitter rival may lose domain 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.