Backpacks, two broken propellers and passports were among the debris scattered on the riverbank where the Lao Airlines turboprop plane left deep skid marks in the ground before disappearing into the water Wednesday.
Thai Foreign Ministry spokesman Sek Wannamethee said search teams had recovered the bodies of 15 crash victims by the time their operations ended Thursday because of darkness and the strong current. He said they were unable to immediately identify them. The last official count issued by Laos of bodies retrieved gave a lower number, nine.
Thailand, which lost five nationals in the crash, is deeply involved in the search, providing skilled manpower and technology that its poorer neighbor lacks.
Yakao Lopangkao, director-general of Lao's Department of Civil Aviation, who was at the crash site in Pakse in southern Laos, ruled out finding survivors.
"There is no hope," he said. "The plane appears to have crashed very hard before entering the water."
He said the plane's fuselage had not yet been found, but was underwater and divers were trying to locate it.
Some of the bodies were found by fishermen floating downstream as far as 20 kilometers (12 miles) from the crash site, he said.
"We have asked villagers and people who live along the river to look for bodies and alert authorities when they see anything," he said.
Fleets of small boats and inflatable rafts plied the muddy, vast waterway as part of the search, with men in life vests peering into the water. After storms Wednesday, the search took place under sunny blue skies.
State-run Lao Airlines released a second updated list of the 44 passengers' nationalities on Thursday. It said the flight included 16 Lao nationals, seven French, six Australians, five Thais, three Koreans, three Vietnamese and one person each from China, Malaysia, Taiwan and the United States. A person who had been listed as a Canadian was instead added to the list of Vietnamese.
The passengers included foreign tourists and expatriates working in Laos.
Tourism has become a major source of income for Laos in the past decade. In 2012, the country received more than 3.3 million foreign tourists who generated total revenue of more than $513 million.
The area where the plane crashed is off the main tourist circuit in Laos but known for its remote Buddhist temples, nature treks and waterfalls.
Cambodian authorities said one of the plane's pilots was a 56-year-old Cambodian with more than 30 years' flying experience.
Details of the crash remained murky. Lao Airlines said in a statement Wednesday that the plane took off from the capital, Vientiane, and "ran into extreme bad weather conditions" as it prepared to land at Pakse Airport. The crash occurred about 7 kilometers (4 miles) from the airport.
The airline said it had yet to determine the cause of the crash of the ATR-72 aircraft, which had been delivered in March.
French-Italian aircraft manufacturer ATR said in a statement that "the circumstances of the accident are still being determined." It said that it would assist in the investigation, which will be led by Lao authorities.
It was the first fatal crash for Laos' state carrier since 2000, when two separate crashes left 23 people dead.
The ATR-72 has been involved in 16 crashes since it went into service in 1988, according to databases kept by the Flight Safety Foundation and the Bureau of Aircraft Accidents Archives. The death toll from Wednesday's crash was the third highest on record involving an ATR-72; accidents in the U.S. in 1988 and Cuba in 2010 each killed 68 people. ATR had delivered 611 of the planes by the end of last year.
Among the six Australians on board was a family of four. Relatives released a photo of the family, Gavin and Phoumalaysy Rhodes and their two children, a 3-year-old girl and a 17-month-old boy.
The other two Australians were a father and son. They were identified as Michael Creighton, a 42-year-old aid worker based in Laos who had worked for the United Nations, and his father, Gordon Creighton, 71, a retired teacher who was visiting his son.
"We have lost a father, a husband, a son, a brother, a fiance and a best mate in one tragic circumstance and we are trying to come to terms with our loss," the family said in a statement. Michael Creighton was living in Laos with his fiancee, who was not on the plane.
Lao Airlines was founded in 1976 after the communist takeover of Laos, operating under the name Lao Aviation until a rebranding in 2003. It originally operated with Chinese- and Soviet-built aircraft, which were replaced in the mid-1990s as part of a major upgrade that included the purchase of ATR turboprops and in 2011 the delivery of two Airbus A320 aircraft.