Lao Airlines says it has located a flight recorder from its crashed ATR 72-600, but that strong currents are preventing rescuers and investigators from retrieving it.
Vice-president Sengpraseuth Mathouchanh says that the river's muddy waters, strong current and depth have hindered effects to recover the device. It is unclear whether the airline has located the flight data recorder or the cockpit voice recorder.
He adds that specific planning needs to be put into the recovery procedure, to "avoid any loss and damage" to the recorder.
The country's civil aviation authority had earlier told the media that search teams have picked up underwater signals which they believe are coming from the recorders of the turboprop.
Recovery efforts for the 16 October crash have been slow because of the bad weather and lack of equipment. The airline has so far recovered 43 bodies, from as far as 25km (13nm) from the accident site. There were five crew and 44 passengers on board flight QV301 when it crashed into the Mekong River.
The turboprop, registered as RDPL-34233, had only accumulated 758 flight hours before the fatal crash. It was delivered new to the airline this March and underwent A-checks in September.