At least 35 people were killed in two separate traffic accidents in China and Thailand, killing 17 and 18 people respectively.

A huge pile-up on a Chinese motorway killed at least 17 and injured 37 people on Tuesday when a total of 56 vehicles crashed into each other in winter weather, said Chinese state media.

"The accident happened due to snow and rainy weather in the northern province of Shanxi, on an expressway linking Beijing with Kunming," reported the official news agency Xinhua.

Pictures of the scene showed lorries scattered haphazardly across the road, some of them overturned, and burnt-out wrecks of cars after the crash.

Traffic accidents are common in China, with the World Health Organisation(WHO) estimating that more than 260,000 people were killed on the country's roads in 2013.

The WHO figures are strikingly higher than official pronouncements, in a country where government data are often questioned, with the National Bureau of Statistics reporting 58,539 traffic fatalities that year ─ less than a quarter of the WHO's approximation.

18 dead as Thai bus plunges into ravine

Eighteen retirees returning from holiday were killed and 20 were injured on Tuesday after their tour bus plunged down a ravine in northern Thailand, police and a media report said, the latest disaster in a country with notoriously dangerous roads, reported Bangkok Post.

The victims were all former employees of state-run company CAT Telecom and were making their way to Bangkok from a province in the mountainous north.

“18 people died and 20 were injured after a bus fell down into deep ravine because the driver was not familiar with the road,” Commander of Uttaradit Police Station Colonel Ditsayadej Patcharapuwadol told AFP.

“The bus was on its way to Bangkok ─ coming down a steep road when it hit a barrier and fell into the 50-metre deep ravine,” he said, adding that the driver was one of those killed in the accident in Muang district of Uttaradit province.

Photos of the crash site posted on social media showed the bus had come to a halt down a steep jungle ravine, its roof almost entirely sheared off.