BOGOTA, March 9 (Xinhua) -- All the 12 people aboard were killed in a plane crash in Colombia on Saturday, said the country's Special Administrative Unit of Civil Aeronautics.

The plane was identified as a Douglas DC-3 registered at the airport in the city of Villavicencio.

"We regret the accident of the aircraft that covered the route (between the municipalities of) San Jose del Guaviare and Villavicencio," tweeted the civil aviation agency.

The agency said in a statement that the aircraft had declared itself in emergency shortly before crashing.

The plane reportedly carried nine passengers and three crew members, including the mayor of Taraira, a municipality located in the southeastern province of Vaupes.

Authorities have launched an investigation into the causes of the accident, said the agency.