New Delhi, March 14 -- All six crew members of a KC-135 refueling aircraft that crashed while supporting operations against Iran are dead, the U.S. military said Friday.

U.S. Central Command, which oversees the Middle East, said the crash in western Iraq on Thursday followed an unspecified incident involving two aircraft in "friendly airspace" and that the other plane landed safely.

Ohio Gov. Mike DeWine said in a social media post that three of the six crew members were from his state and deployed with the Ohio Air National Guard's 121st Air Refueling Wing. He did not identify them but offered condolences to their families.

The crash brings the U.S. death toll in Operation Epic Fury to at least 13 service members, with the seven other...