South Korean police say their chief received the first report about Saturday's deadly crowd crush in Seoul two hours after the incident.

The National Police Agency said Commissioner General Yoon Hee-keun was informed about the crush in the Itaewon district at 12:14 a.m. on Sunday. In the tragedy, 156 people have been confirmed dead.

At that time, South Korean media had already started reporting the accident, saying more than 50 people were likely suffering from cardiac arrest.

Police received reports about overcrowding hours before the crush. Yoon indicated the police's response was inadequate.

The presidential office says President Yoon Suk-yeol was informed about the incident at around 11 p.m. on Saturday.

South Korean media say senior officials' slow response to the chaos may be a factor behind the large number of victims. They also say those officials may be held accountable.

Two Japanese were among the dead. One of them was 26-year-old Tomikawa Mei. On Wednesday, her parents visited a venue in Seoul where flowers have been laid for the victims.

They were accompanied by members of the Japan-South Korea parliamentarians' union. Mei's father thanked the lawmakers.

A large number of people have been visiting the venue to mourn the victims.