Secretary of State Rex Tillerson Rex Wayne TillersonGary Cohn: 'I haven't made up my mind' on vote for president in November Kushner says 'Alice in Wonderland' describes Trump presidency: Woodward book Conspicuous by their absence from the Republican Convention MORE said on Sunday former White House aide Sebastian Gorka was "completely wrong" to criticize the president's Afghanistan speech because there was no mention of "radical Islam."

"It shows a lack of understanding of the president's broader policy when it comes to protecting Americans at home and abroad from all acts of terrorism," Tillerson told Chris Wallace on "Fox News Sunday."

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"Terrorism has manifested itself in many types of organizations. The president has charged us to develop policies and tactics both diplomatically and militarily to attack terrorism in its many forms, wherever it exists in the world, and wherever it might present a threat to the homeland or Americans anywhere. This means that we need to develop techniques that are global in their nature."

Tillerson was responding to a line from Gorka's resignation letter, in which he said, "The fact that those who drafted and approved the speech removed any mention of Radical Islam or radical Islamic terrorism proves that a crucial element of your presidential campaign has been lost."

The White House announced Gorka's departure on Friday evening, just one week after his ally, Stephen Bannon, left his post as White House chief strategist.