Fire fighters work at the scene of a multi-vehicle pileup in a tunnel on a highway in Namwon, South Korea, Monday, Feb. 17, 2020. The major highway pileup occurred amid snowy weather in the country's southwest. (Na Bo-bae/Yonhap via AP)

Fire fighters work at the scene of a multi-vehicle pileup in a tunnel on a highway in Namwon, South Korea, Monday, Feb. 17, 2020. The major highway pileup occurred amid snowy weather in the country's southwest. (Na Bo-bae/Yonhap via AP)

SEOUL, South Korea (AP) — Four people were killed and 43 were injured Monday in a highway pileup in snowy weather in southwestern South Korea, officials said.

The Jeonbuk Provincial Police Agency said the pileup involved about 30 vehicles, including a chemical truck carrying nitric acid that flipped over and caught fire inside a tunnel.

Police official Jeon Gwang-hun said he couldn’t provide further details because the investigation of the cause of the accident was continuing.

Kim Jun-ho, an official from the Korea Expressway Corporation, said its workers had removed snow in the area before the accident and it wasn’t immediately clear whether the accident was caused by icy road conditions or careless driving.