Lao Airlines says it is working with local authorities and ATR to identify the cause of the fatal crash of its ATR 72-600 near Pakse, and would not confirm whether bad weather had a role to play in the tragedy.

The flag carrier says the accident happened at 15:55 local time as it was operating flight QV301 from Vientiane to Pakse.

The seven-month old turboprop apparently crashed into the Mekong River while attempting to land at Pakse airport. The airport has a single runway that runs parallel to the eastern shore of the Mekong River.

Lao Airlines says there were 49 people on board, including two pilots, two flight attendants and one mechanic. The 44 passengers came from 11 countries, including France, Australia and Korea.

"Tragically, we expected there are no survivors. My deepest condolences go out to all families affected by this tragic accident," says chief executive Somphone Douangdara.

He adds that the airline has set up a special team to work with Laotian aviation authorities as well as ATR to identify the cause of the accident.

A spokesman at the carrier would not say whether bad weather played a part in the crash, or whether the aircraft's flight data recorder and cockpit voice recorder have been recovered.

ATR had earlier disclosed official sources at the carrier had said that the aircraft "ran into extreme bad weather conditions" before crashing into the Mekong River.

The airframer said that the aircraft involved, registration RDPL-34233, was delivered new to the airline only in March this year.

Flightglobal Pro data shows that Lao Airlines operates a fleet of 14 aircraft including six ATR 72s, four Airbus A320s and four Xian Aircraft MA60s. It operates services within Laos and to neighbouring countries in Asia.