All passengers and crew _ from a dozen countries _ were presumed dead after the turboprop ATR-72 came down in stormy weather on Wednesday, sinking to the bottom of the swollen waters.
As rescuers scoured the river for the submerged plane, a crane perched on a floating platform in the middle of the Mekong was on standby to try to winch up the aircraft.
About 10 boats of varying sizes plied the fast-flowing waters and divers from a Thai rescue team were on the scene to assist.
"It's difficult to dive because there is a strong current and it's dangerous. So I think it's 50/50 that we will find something," said Thai rescue diver Aniwat Plaeng-ngaan, 20.
Lao authorities yesterday allowed more than 100 rescue workers and divers from Thai private relief organisations, naval and police forces to assist with the search for bodies. Five Thai nationals were on board the plane.
As of 4.05pm Thursday (the same time in Thailand), 16 bodies had been found, the Thai Emergency Medical Service (EMS) Info website reported.
Retrieved bodies of the victims will also be sent to Sapphasitthiprasong Hospital in Ubon Ratchathani for identification. Lao authorities also requested body bags from the Thai hospital to handle bodies.
A Thai Tsunami Victim Identification team will travel to Ubon Ratchathani and Pakse today at the request of Lao authorities and the Australian embassy in Bangkok to help identify victims.
Crowds of local people, monks and security personnel watched from the banks. Some recounted seeing the plane in trouble before it came down.
"I heard a boom! A sound like a bomb going off. There was smoke and flames before it crashed," said village chief Buasorn Kornthong, 37.
Some debris was seen floating along the river and suitcases were wedged in mud on the riverbank.
The flight from the capital Vientiane was carrying 44 passengers and five crew, including 28 foreigners, when it crashed near Pakse airport in Champasak province, according to officials.
"Tragically, we expect there are no survivors," Lao Airlines CEO Somphone Douangdara said yesterday, expressing "deepest condolences" to families of the victims.
Some of those killed were taken to a Chinese-run mortuary in Pakse town, which is a hub for tourists travelling to some of the more remote areas in southern Laos.
Three bodies draped in blue plastic sheets were seen in the building, which was guarded by 10 police, some armed, who turned away onlookers.
"They are foreigners from the crash," staff at the centre said, adding that their nationalities were unknown.
Lao Airlines said the aircraft hit "extreme" bad weather while witnesses described seeing the aircraft buffeted by strong winds.
"The plane was about to land but appeared to be hit by a strong gust, causing its head to ascend and pushing it away from the airport area and out of reach of the air traffic control radar," state-run Laos news agency KPL quoted a witness as saying.
French President Francois Hollande learned of the disaster "with profound emotion and great sadness", his office said.
According to a passenger list from the airline, there were 16 Lao, seven French travellers, six Australians, five Thais, three South Koreans, two Vietnamese, and one national each from the US, Canada, Malaysia, China and Taiwan.
Cambodia's civil aviation office said the pilot was one of its nationals and had "many years" of flying experience.
Deputy Prime Minister and Foreign Minister Surapong Tovichakchaikul on Thursday extended condolences to families of the victims and offered to help Laos in handling the incident.
Thailand's national oil and gas conglomerate, PTT Plc, confirmed three of the passengers on board _ two Thais and one Lao national _ were its employees who were assigned to inspect oil retailing facilities in Pakse.
"We want to express condolences for the loss of our invaluable human resources in this accident and we will take good care of their families," said Chavalit Punthong, executive vice-president for oil retail marketing.
Flight QV301 set off from Vientiane on time at 2.45pm on Wednesday and was supposed to arrive in Pakse just over an hour later.
French-Italian aircraft manufacturer ATR said the twin-engine turboprop aircraft was new and had been delivered in March.
The company said "the circumstances of the accident are still being determined".
It said that it will assist in the investigation which will be led by Lao authorities.
Founded in 1976, Lao Airlines serves domestic airports and destinations in China, Thailand, Cambodia and Vietnam.
Impoverished Laos, a one-party communist state, has had 29 fatal air accidents since the 1950s, according to the Aviation Safety Network, whose data showed that the country's safety record had improved dramatically in the last decade.
The last fatal air accident was in October 2000 when eight people died after a plane operated by the airline _ then called Lao Aviation _ crashed in remote mountains in the northeast of the country.Families mourn Australian victims of doomed flight
A Sydney family of four and an Australian aid worker and his father were among the victims of a plane crash in Laos believed to have killed all 49 people on board.
Relatives released a photograph of 39-year-old tax consultant Gavin Rhodes, his 35-year-old wife Phoumalaysy Rhodes, and their children, Jadesuda, aged 3, and 17-month-old Manfred.
A passenger manifest from Lao Airlines had identified Jadesuda Rhodes as Lao, but the airline later confirmed all four family members were Australian.
The other two Australian victims were Michael Creighton, 42, an aid worker based in the Lao capital, Vientiane, and his 71-year-old father, Gordon Bruce Creighton, from the New South Wales town of Glen Innes.
The Lao government said 49 people were on the plane that crashed in stormy weather on Wednesday while heading from Vientiane to Pakse in southern Laos, and that there was no hope of finding any survivors.
Michael Creighton was an operations manager at Norwegian People's Aid's mine action programme and lived in Laos with his fiancee, Melanie Fuller, who was not on the plane.
''I have lost the love of my life, my heart, my soul, my future, my children, my world and myself,'' Ms Fuller posted on her Facebook page. ''For everyone wondering, that is the loss I will live with forever.''
Michael Creighton was a former member of the Australian Defence Force and later worked for the United Nations.
He spent the past 20 years doing humanitarian work in countries including Afghanistan, Iraq, Switzerland and Cambodia.