The two persons identified as 54-year-old Dambru Tangal of Aringi village and 62-year-old Hari Khora of Dukamput village in Nandapur block were returning from Rabel village in an unregistered boat, the sources said.
A senior district official said that there was a problem in getting information because of the remoteness of the area and absence of telecommunications.
An ODRAF team has been sent to the spot.