The return of mechanized units also comes as the U.S. military deployed Sentinel radar and increased the frequency of fighter jet patrols over U.S. forces in that part of Syria, according to U.S. Central Command spokesman Navy Capt. Bill Urban. “These actions are a clear demonstration of U.S. resolve to defend Coalition forces in the Eastern Syria Security Area, and to ensure that they are able to continue their Defeat-ISIS mission without interference,” Urban said in an emailed statement. “The Defense Department has previously deployed Bradleys to northeast Syria pursuant to these goals."