The Marines recently completed a live-fire exercise in Syria – the one place more hostile to human life than Twentynine-Palms – during which they trained with Syrian rebels backed by the U.S. government, according to U.S. Central Command.

Operation Apex Tuefelhunden was conducted from Sept. 7-11 near the At Tanf garrison in eastern Syria, according to pictures released by the Marine Corps on Friday. The company-sized element from 3d Battalion, 7th Marine Regiment was attached to Special Purpose Marine Air-Ground Task Force, Crisis Response-Central Command.

“Our forces will demonstrate the capability to deploy rapidly, assault a target with integrated air and ground forces, and conduct a rapid exfiltration anywhere in the OIR combined joint operations area,” CENTCOM spokesman Navy Capt. Bill Urban said in a Sept. 7 news release.

Marines partnered with the Syrian opposition group Maghawir Al-Thawra – or “Commandos of the Revolution” – which has partnered with the U.S.-led coalition to defeat ISIS in Syria. The exercise took place in the 55-kilometer de-confliction zone around At Tanf, which separates U.S. troops and Syrian partner groups from Syrian regime forces and their Russian allies.

Russia reportedly threatened to attack the de-confliction zone prior to the exercise, claiming that it was a haven for ISIS fighters. “The U.S. does not require any assistance in our efforts to destroy [Islamic State] in the At Tanf de-confliction zone, and we advised the Russians to remain clear,” CENTCOM spokesman Lt. Col. Earl Brown told the Los Angeles Times on Sept. 7.

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