Dag Mejdell, CEO of the Norwegian postal service, says debris has been spotted near the Akkajaure reservoir in Sweden's sparsely populated Lapland region.
The postal service had hired the Canadair CRJ 200 aircraft to fly mail to northern Norway.
A mayday message was sent out late Thursday near Akkajaure after which contact with the jet was lost. The cause of the crash wasn't immediately known.
Mejdell said Friday it was "a very serious and tragic accident."