Rescue workers are searching Bolivia's eastern jungle for a missing twin-engine plane with nine people aboard operated by a small commercial airline.

The Aerocon Fairchild SA227-DC Metro went missing Tuesday evening on approach to Trinidad, the provincial capital of Beni. It had originated in the eastern city of Santa Cruz.

Authorities say two Colombians and seven Bolivians were aboard.

Aerocon official Nelson Kin says air traffic controllers did not receive an alert from an alarm aboard the plane that is designed to go off if it crashes.

A local military commander said in a television interview Wednesday that dense smoke from forest fires in the area impeded the search.