A massive landslide and boulders buried a passenger bus travelling on a popular backpacker route, killing six people and injuring 19 others. Heavy rainfall in Vietnam caused Earth and rocks to tumble from the mountainside along the Khan Le pass in the country's central highlands on Sunday night.

The bus was travelling on the popular tourist route through the scenic highlands of the Southeast Asian nation, which has become increasingly visited by holidaymakers and backpackers seeking a cheaper destination than nearby Thailand. The 20-mile-long, winding stretch of road is carved into steep mountain sides and has been prone to landslides during the rainy season.

It's reported that the landslide crushed the front of the bus, trapping many of the passengers on board. Rescuers struggled for hours to reach the scene as heavy rain had also caused landslides on both sides of the pass, cutting off access. Rescue teams were only able to reach the bus after midnight, state media said.

It's understood the Foreign Office have not been approached concerning the incident.

The bus was carrying 32 people from Vietnam's northern financial capital, Ho Chi Minh City and was travelling from Da Lat in Vietnam's central highlands to the coastal city of Nha Trang.

The injured passengers were taken to a nearby hospital. State media said two of the dead bodies were still trapped under the debris as the treacherous terrain hindered the work.

Heavy rain has been pounding central Vietnam, which was earlier hit hard by Typhoon Kalmaegi. Rainfall this week up to Wednesday is expected to reach 12-24 inches in the central parts of the tropical country, with some areas likely to exceed 85 33 inches.

Heavy rain caused flooding and landslides in mountainous areas of Hue city on Sunday, blocking a major highway that runs from northern to southern Vietnam and cutting off several villages.

The former imperial capital has already endured historic floods this year.

Vietnam is among the world's most flood-prone countries, with nearly half its population living in high-risk areas.

Scientists warn that a warming climate is intensifying storms and rainfall across Southeast Asia, making floods and landslides increasingly destructive and frequent.