An investigation is underway after a Delta regional jet bound for North Dakota was forced to make an “aggressive maneuver” to avoid a potential mid-air collision with a U.S. Air Force B-52 bomber.

The incident occurred on July 18, though it remains unclear exactly how close the two aircraft came to one another.

The flight, operated by SkyWest on behalf of Delta Air Lines, was en route when the close call prompted immediate action by the crew. SkyWest confirmed it is actively investigating the incident.

No injuries or damage were reported, and both aircraft continued safely. Aviation officials have not released further details as the review continues.