South Korea's police chief has admitted to obvious mistakes by his agency after the stampede that killed more than 150 people during Halloween parties in Seoul.

In the hours leading up to Saturday night's tragedy, several emergency calls were received indicating potential dangers, National Police Agency chief Yoon Hee Keun said on Tuesday.

But the answer to that was "insufficient": "I feel a heavy responsibility as the head of one of the responsible authorities."

Yoon did not say whether, from his point of view, the catastrophe could have been prevented by early police measures.

But he wanted to ensure that what went wrong was thoroughly investigated.

An independent investigative body will also be created within the police authority.

What role did the authorities play?

The mass accident not only caused horror and sadness in South Korea.

It also triggered critical questions about the role of the authorities and the lack of security precautions.

The accident in the metropolis of millions happened when tens of thousands of people crowded together in the popular nightlife district of Itaewon for unorganized Halloween celebrations.

Numerous people were trapped in the extreme crowds in a narrow and sloping side street.

Many fell to the ground, suffocated, were crushed or kicked to death.

Prime Minister Han Duck Soo hinted at a news conference on Tuesday that police should be given a freer hand in directing mass events with no apparent organizer.

"The most important factor was crowd management," he said, referring to the disaster.

This revealed deficits.

"We should change the system completely." However, he could not go into detail because of the ongoing investigations.

Interior Minister Lee Sang Min and Seoul Mayor Oh Se Hoon both apologized for the mass accident.

As mayor, he feels a limitless responsibility, Oh said.

He promised the city would do its best to improve security at mass gatherings.

Other victims died

According to the Ministry of the Interior, the number of mostly young fatalities increased to 156. Two people have died from their injuries since Monday night.

According to the updated figures, 151 injured were recorded.

Of them, 29 are in critical condition.

Among the fatalities were 26 foreigners from different countries.

Itaewon attracts crowds, especially on weekends, with its club scene and numerous pubs.