The police on Thursday conducted their first interrogation on the driver behind the deadly crash in downtown Seoul on Monday night that killed nine and injured seven others.

Namdaemun Police Station questioned the 68-year-old driver surnamed Cha for around two hours at the hospital where he's being treated.

Cha claims that sudden unintended acceleration was the cause of the accident, adding that the driver tried applying the brakes but was not able to press down on it.

Police say they will conduct follow-up questioning at a later time with the presence of his lawyer.

Meanwhile, the Seoul Central Court on Wednesday dismissed a pretrial detention warrant request filed by the police saying it's difficult to determine the necessity for a detainment.