Retired four-star Gen. Jack Keane slammed the Obama administration's handling of the Islamic State threat Tuesday following the killing of a 26-year-old American aid worker held by the terror group.

Appearing on Fox News' "America's Newsroom," Keane said in response to Kayla Mueller's death:

"The barbarism has been growing and expanding. No one can dispute the fact that radical Islam has morphed into a global jihad… and that expansion has been going on largely during the president's administration. Not to accept that, one… is a major failing. And two, then to diminish it, that runs against the very harsh facts that are out there."

Keane referenced comments the president gave in an interview published by Vox on Monday where he compared his role in fighting terror to a "big city mayor" fighting crime.

"[That's] disturbing and it's reckless, because it's dangerous to the American people," Keane said.

"Certainly these tragedies that we see unfold in Africa, in the Middle East that ISIS is doing, they all share a common connected tissue, and that is an ideology. We need to press against it, and it's obvious that this president is not going to do that."