At least 12 people were killed and more than 20 seriously injured in a single road accident on Monday as millions of South Koreans headed home for the Chuseok holiday, police said.
The accident involving more than 30 vehicles occurred on the West Sea Grand Bridge on the West Coast Expressway, around 70 kms southwest of Seoul, after a 12-tonne truck rammed a smaller truck.
The collision sparked a blaze that engulfed some 20 vehicles, bringing northbound traffic on the expressway to a halt.
"So far, at least 12 people were confirmed dead and some 20 others were injured," a police officer said.
More than 20 fire trucks were mobilised to put out the blaze and pull victims from their mangled vehicles.
The accident caused severe jams on the expressway and nearby roads as millions began their annual exodus to hometowns to visit relatives and ancestors' tombs.