A car hit pedestrians near Seoul city hall, killing nine people and injuring at least four, South Korean media reports said, citing police and fire officials.
A police official told Reuters that officers were investigating the scene and declined to give further information.
YTN TV reported that the vehicle rammed into pedestrians standing on the crosswalk after hitting two other cars.
A police officer was administering CPR to a person on the ground at the site of the accident, according to a video provided by a witness to Reuters.