Aerial view of damaged vehicles after the pile-up on the Beijing--Kunming Expressway in Pingyang, north China's Shanxi province, 21 November 2016.

Four people were killed and another 40 injured in an accident when a pile-up on an expressway in north China's Shanxi province, Monday (21 November 2016) morning. The pile-up took place around 9:00 am and 37 vehicles were involved in the accident on the highway linking Beijing and Kunming. Slippery road as a result of heavy fog was thought to be the cause of the pile-up.
Huge deadly pileup in China
00:59 - Source: CCTV
Beijing CNN  — 

Slippery conditions and fog are thought to have contributed to a huge highway pileup that killed 17 people in northeastern China.

The crash involved 56 vehicles on the Beijing-Kunming highway in China’s Shanxi province around 9 a.m. Monday, according to state news agency Xinhua.

“The fog was heavy, so I drove slowly when I exit the tunnel,” one driver involved in the incident told state-run CCTV. “I saw two vehicles horizontally blocking the road, so I stepped on the brake.”

Aerial view of damaged vehicles after the pile-up on the Beijing--Kunming Expressway in north China's Shanxi province.

It had been snowing and raining before the accident, which also injured 37 people, Xinhua said.

Firefighters told CCTV that when they arrived they fought a blaze at the front of the pileup.

“While some of us manned the hoses, a chief officer led the rescue efforts of trapped personnel,” firefighter Wang Ruobing said.

The road was blocked as rescuers worked to free those trapped.

A day after the collision the highway was still closed to traffic, according to the Shanxi Traffic Control Center. An investigation is underway.