The photo shows a heavily damaged vehicle at the site of a car crash that killed at least nine people in central Seoul, July 1. Yonhap

At least nine people were killed and four others injured when a sedan crashed into pedestrians in downtown Seoul on Monday night, police said, creating chaos in the typically crowded metropolitan street.

The accident took place at an intersection near Seoul City Hall at around 9:27 p.m, police said, as the vehicle, driven by a 68-year-old man, plowed into pedestrians who were waiting at a traffic signal. The driver is said to blame a sudden unintended acceleration for the accident.

Of the nine fatalities, six died at the scene, while three were transported to a hospital in cardiac arrest and later pronounced dead. Among the four injured, one returned home after treatment, while the others are not in critical condition.

The vehicle was driving in the wrong direction and collided with two vehicles before hitting people, according to the police. Police apprehended the driver who was not under the influence of alcohol according to an initial examination.

Rescue workers are at the site of a car crash that killed at least nine people in Seoul, July 1. Yonhap

President Yoon Suk Yeol was briefed on the accident and ordered Interior Minister Lee Sang-min and other aides to make "all-out" efforts to save and treat the victims.

Lee also issued an emergency order to mobilize all available resources to save the lives of those affected by the accident.

Seoul Mayor Oh Se-hoon rushed to scene of the accident.

"It is a sad accident," he said, calling on his staff to promptly take victims to the hospital and thoroughly get to the bottom of the case.

Police are investigating the exact circumstances of the accident.

Debris is strewn around a sidewalk where a vehicle jumped the curb and killed at least nine pedestrians in downtown Seoul, July 1. Yonhap

The driver of the sedan and his wife were transported to a hospital as he complained of pain.

He has claimed that his car suddenly accelerated. It has yet to be determined whether he was under the influence of any drugs or if drowsy driving was a factor in the accident.

"As the driver was also hurt, we have yet to proceed with our investigation," a police official said in a briefing. "We will conduct an inquiry when he becomes available to speak."

The official added that a preliminary probe suggested the driver was not drunk at the time of the accident.

"With regards to the cause of the accident, we will swiftly and sternly carried out our investigation based on the driver's statements, closed-circuit television and security camera analysis," he said.

Security camera footage showed a citizen conducting cardiopulmonary resuscitation on a person lying on the ground as it underscored the sense of urgency following the accident.

The accident came amid questions over whether measures should be considered to help ensure safe driving among senior citizens. (Yonhap)

An official from central Seoul's Jung District speaks during a briefing on the car crash that killed at least nine in downtown Seoul, July 1. Yonhap

The site of a car crash in central Seoul which killed at least nine people on July 1 / Yonhap