NORWAY – A loud boom that jolted western Mainers awake may have been a sonic boom from an aircraft, but an official said it wasn’t caused by a plane from the Brunswick Naval Air Station.

People in parts of Androscoggin and Oxford counties reported hearing the explosionlike noise just before 9 Thursday morning.

An Oxford County police dispatcher said several calls came in from Oxford and Hebron, but there was no official determination of the source of the noise.

Spokesman John James of the Brunswick Naval Air Station said he was unaware of any military training exercises in the area. James also said the noise was not created by aircraft from that base because it’s impossible for any of its aircraft to go supersonic.