Similar to the buildup ahead of last June’s strikes on Iran’s underground nuclear enrichment facilities, sources say military aircraft at Al Udeid Air Base in Qatar—including roughly a dozen U.S. Air Force aerial refueling tankers—have either been evacuated or are preparing to relocate to other bases inside and outside the Middle East.

Satellite imagery from last year showed Al Udeid completely cleared of aircraft by June 17, ahead of U.S. strikes on Iranian nuclear sites on June 22 and Iran’s retaliatory ballistic missile attack on the base the following day.