The crowd control during the Halloween celebrations in South Korea’s Seoul was inadequate, the country’s police chief said on Tuesday, acknowledging for the first time that officials did not not do enough to prevent the stampede that led to over 150 deaths, reported the BBC.

The disaster occurred on October 29 in the city’s Itaewon area – a locality popular for its nightlife – where an estimated one lakh people had gathered. Most of those killed were in their 20s, according to the BBC. The toll has climbed to 156 from 151 with 29 seriously injured, reported Reuters.

On Tuesday, National Police Commissioner Yoon Hee-keun said the police response was disappointing and that he felt “limitless responsibility about public safety” over the accident.

Yoon said that he will do his best to ensure that such a tragedy does not happen again.

The police chief also said officials had received several phone calls before the accident happened, alerting them to the seriousness of the situation. He said that the police would conduct a speedy investigation to see if proper action was taken after receiving the calls, and if officers had reacted appropriately.

The statement follows growing demands in the country for accountability after the authorities portrayed the crowd crush as an incident that could not have been prevented, according to the BBC. Defending the government, Interior Minister Lee Sang-min had said deploying more personnel would not have helped in the situation.

However, President Yoon Suk-yeol said on Tuesday the incident showed that crowd management was important and that there is a lack of research in the country on the subject.

“Rather than nitpicking about whether the event had an organiser or not, it’s the people’s safety that’s important, and we need to come up with thorough measures,” he said, suggesting that drones and other digital gadgets could be used to manage crowds in future events.