The Antonov-24 belonging to the Angara airline was carrying 33 passengers between Tomsk and Surgut when an engine apparently caught fire forcing it to ditch in the river in the Tomsk region of Siberia, the investigative committee said in a statement.

"The preliminary version is that the accident happened because an engine caught fire," investigators said.

A total of 21 people were taken to hospital in the nearby town of Strezhevoi after the emergency landing, the RIA Novosti news agency reported, citing a doctor in accident and emergency.

Copyright AFP (Agence France-Presse), 2011