A Lao Airlines plane crashed into the Mekong River in southern Laos with 49 people on board, about half of whom were foreigners, the airline said on its Facebook page.
All 44 passengers and five crew members were presumed dead although a search was still under way for survivors in the river, the state-owned airline reported.
The ATR 72-600, a twin-engine turboprop aircraft, crashed near Pakse, the capital of Champasak province, about 4 pm (0900 GMT) after flying into a rainstorm, the airline said.
The passenger list included 17 Laotians, seven French nationals, five Australians, five Thais, three South Koreans, two Vietnamese, one Chinese, one Canadian, one Myanmar national and one person from Taiwan.
Relatives of the passengers had been informed of the accident, Lao Airlines said.
Photos of the aircraft partially submerged in the Mekong near Done Kho Island were posted on a number of Facebook pages.