The special police investigative team probing the deadly Itaewon crowd crush summoned the former Yongsan police chief and the Yongsan fire chief as suspects for questioning on Monday.

Appearing at the Seoul Metropolitan Police Agency's Mapo complex in the morning, ex-Yongsan police chief Lee Im-jae apologized as the official with on-site command responsibility at the time of the tragedy.

Lee is accused of failing to take precautionary measures ahead of Halloween festivities despite an expected mass gathering of people, then arriving at the scene of the tragedy some 50 minutes later, further delaying the police response.

Yongsan Fire Station chief Choi Seong-beom, who also arrived for questioning, is accused of causing increased fatalities after failing to act to a police request for joint response prior to the tragedy and for not taking appropriate measures immediately afterward.