(CNN) A Delta Air Lines flight returned to Austin-Bergstrom International Airport in Texas on Saturday due to mechanical issues that may have been caused by a drone or bird strike, officials said.

Flight 1281, departing Austin for Salt Lake City, Utah, "landed safely and returned to the gate, where customers deplaned normally," Delta said in a statement.

There were 126 passengers and five crew members aboard the Airbus A319, Delta spokesperson Savannah Huddleston told CNN.

The initial report was that the plane might have struck birds, but the nature of the problem is still under investigation, Bryce Dubee, a spokesperson for the Austin airport, told CNN.

"We've seen reporting that it was a drone, or a bird-strike but the plane is currently being examined at the airport to determine the nature of the mechanical issue," Dubee said.

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